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kryton1212
Group Title
The graph of y=ax^(2)+bx+c is given as shown. Which of the following is / are true?
I. a<0
II. b<0
III. c<0
A. I only
B. I and II only
C. I and III only
D. II and III only
E. I, II and III
 2 years ago
 2 years ago
kryton1212 Group Title
The graph of y=ax^(2)+bx+c is given as shown. Which of the following is / are true? I. a<0 II. b<0 III. c<0 A. I only B. I and II only C. I and III only D. II and III only E. I, II and III
 2 years ago
 2 years ago

This Question is Closed

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352549825053:dw
 2 years ago

Kira_Yamato Group TitleBest ResponseYou've already chosen the best response.0
(C) c < 0 as graph cuts yaxis below the xaxis a < 0 because graph is frowning curve
 2 years ago

hashsam1 Group TitleBest ResponseYou've already chosen the best response.1
E) inverted U shape meaning a<0 intersecting y axis at negative means C is less than 0 c<0 and also there is shift along x axis in right direction means b<0
 2 years ago

Kira_Yamato Group TitleBest ResponseYou've already chosen the best response.0
Overlooked the detail for b<0... Sorry
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
I am confusing why b>0 is correct
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
the line of symmetry x = b/2a, is a positive value, and we know a < 0 so b > 0
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
I am sorry that I type it wrongly. It should be : "I am confusing why b<0 is correct"
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
b > 0 is correct.
 2 years ago

03225186213 Group TitleBest ResponseYou've already chosen the best response.0
a<0 because parabola opens downward
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
I know a<0 and c<0, I just don't know why b<0 is correct
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
b < 0 is NOT correct.
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
so the answer is C?
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
yes. a < 0 and c < 0.
 2 years ago

hashsam1 Group TitleBest ResponseYou've already chosen the best response.1
dw:1352551798883:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
@hashsam1 the line of symmetry is the line x = b/2a. according to the graph it is to the right of the yaxis (so the sign of b/2a is positive). we know that a < 0, so if b < 0 then the sign of b/2a is ()/2() is negative.
 2 years ago

phi Group TitleBest ResponseYou've already chosen the best response.0
a simple example with 2 positive roots x=1 and x=2 the polynomial would be (x1)(x2) = x^2 +3x 2 this suggests a<0 b>0 c<0
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
I understand now, thank you so much :)
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
another question If f(x)=x(1/x), then f(x)f(1/x)= ?
 2 years ago

hashsam1 Group TitleBest ResponseYou've already chosen the best response.1
oops yes right i over looked the equation thinking its just a normal quadratic equation.
 2 years ago

phi Group TitleBest ResponseYou've already chosen the best response.0
If f(x)=x(1/x), then f(x)f(1/x)= ? replace f(x) with x 1/x replace f(1/x) with 1/x  x
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352552240065:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352552332194:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
yup, that's right.
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352552484497:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
1/(1/x) = x. try again.
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
oh .dw:1352552602486:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
you still need to combine x + x
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
2x(2/x)
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
that's right!
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352552793347:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
i'll accept either form.
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
another question If f(x)=10^(2x), then f(4y)=?
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
A. 10^(4y). B. 10^(2+4y) C. 10^(8y) D. 40^(y) E. 40^(2y)
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
replace x by 4y, what do you get?
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
\[\huge 10^{2(4y)}\]
 2 years ago

nubeer Group TitleBest ResponseYou've already chosen the best response.0
f(x)=10^(2x) f(x)=10^(2(4y))
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
If f(x)=x/(1x), then f(1/x)f(x)=?
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
@gerryliyana
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
and your answer is?
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352553510302:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
\[\huge f(x) = \frac{ (x) }{ 1(x) }\]
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
errrr.....wait
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
If f(x)=x/(1x), then f(1/x)f(x)= f(1/x) = (1/x)/(1(1/x)) = 1/x((x1)/x) f(x) =(x)/(1(x)) = x/(1+x) f(1/x)f(x) = 1/x((x1)/x) times x/(1+x) f(1/x)f(x) = x/(x((x1)/x)(1+x))
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
o.o errrr.... wait a moment
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
f(1/x)f(x) = x/(x((x1)/x)(1+x)) f(1/x)f(x) = x/((x1)(x+1))
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554094668:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554171343:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
dw:1352554209982:dw
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554144569:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
is it necessary for you to give me a big cross....... I got it :)
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554351232:dw
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554433711:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554512663:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
dw:1352554536556:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554601402:dw
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554549107:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
dw:1352554649051:dw
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554682501:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
we're not discussing' we're exchanging notes. hahaha
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554679681:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
haha :))
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554776614:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352554942585:dw
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
what's the answer to your problem \[\huge f(\frac{ 1 }{ x })f(x)\]
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
oh my god
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
A. 1/2 B. 1 C. (1x)/(1+x) D. x/(1x^(2)) E. x/(x^(2)1) no answer since this is past paper, my teacher haven't give us the answers yet
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
I still cannot get the answer
 2 years ago

Callisto Group TitleBest ResponseYou've already chosen the best response.1
Please start a new post for a new question. If possible, please also put them in the right categories (subtopics). Thanks!
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
\[\large f(1/x)f(x) = \frac{ 1/x }{ 11/x }\frac{ (x) }{ 1(x) }\] \[\large = \frac{ 1 }{ 1+x \frac{ 1 }{ x }1 } \times \frac{ x }{ x }\]
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
so complicated....
 2 years ago

sirm3d Group TitleBest ResponseYou've already chosen the best response.2
just carry out the multiplication and you'll get (D)
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
dw:1352556469608:dw I get this only...
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
f(1/x)f(x) = x/(x((x1)/x)(1+x)) f(1/x)f(x) = x/((x1)(x+1)) f(1/x)f(x) = x/(x^2 1) f(1/x)f(x) = x/(x^2 +1) f(1/x)f(x) = x/(1x^2) the answer is D x/(1x^2)
 2 years ago

gerryliyana Group TitleBest ResponseYou've already chosen the best response.0
you got it @kryton1212 ???? take it a simply way..,hehe
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
confusing................. I think it later another question If a,b and c are all positive, which of the following may represent the graph of ax+by+c=0?dw:1352556954406:dw
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
@hartnn would you kindly help me?
 2 years ago

Callisto Group TitleBest ResponseYou've already chosen the best response.1
@kryton1212 Please start a new post for a new question!
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
the problem is I cannot draw picture in a new post
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
ok, let this be last question discussed in this post, agreed @kryton1212 ? for this u know how to find intercepts ?
 2 years ago

Callisto Group TitleBest ResponseYou've already chosen the best response.1
You can post the question a draw it in the comment
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
@hartnn that's ok. c=yintecept
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
nopes, c is y intercept in y=mx+c not here
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
to get x intercept, put y=0 in ax+by+c=0 to get y intercept, put x=0 in ax+by+c=0
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
now tell me what intercepts u get
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
....oh yes. I don't know how to find the intercept in these gaphs
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
to get x intercept, put y=0 to get y intercept, put x=0 in any graphs
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
ax+by+c=0 put y=0??? ax+c=0?
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
yes, thats right ax+c=0 x= ?
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
absolutely correct! now c/a is positive or negative ?
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
given a and c are positive....
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
so your xintercept is negative, that is it will cut x axis in negative (left) side got this ? what about yintercept ???
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
so it may be B or E. y=c/b is it E?
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
yes, y intercept is also negative, so it will cut down. and yes its E clear as to how ?
 2 years ago

kryton1212 Group TitleBest ResponseYou've already chosen the best response.0
clear now, thank you
 2 years ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
make sure u ask next question in new post...
 2 years ago

phi Group TitleBest ResponseYou've already chosen the best response.0
@kryton1212 it would be better if you made each question a separate post.
 2 years ago
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