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 2 years ago
If the graph of the quadratic function f(x) = x^2 + dx +3d has its vertex on the x axis what are the possible values of d? What if f(x) = x^2 + 3dx +1?
 2 years ago
If the graph of the quadratic function f(x) = x^2 + dx +3d has its vertex on the x axis what are the possible values of d? What if f(x) = x^2 + 3dx +1?

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mukushla
 2 years ago
Best ResponseYou've already chosen the best response.1complete the square for x^2 + dx +3d to get its vertex

meera_yadav
 2 years ago
Best ResponseYou've already chosen the best response.1mukushla is right :) try doing ...

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1I have the answers. Easily accessible in the back of the book. How to solve it is the problem. When you say complete the square what do you mean? I've been trying x^2 + dx +3d = ax^2 + (2ah)x+ (ah^2+k) And trying to identify the vertex.. that waayy... But what do you mean by complete the square?

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1the vertex of quadratic equation is given by (b/2a, cb^2/4a) since it has vertex on X axis therefore y ordinate =0 . hence cb^2=0

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1Thanks! I'll try it again.

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1in 1st case the value of d=0 and 3 in 2nd case d=1/3 and 1/3

mukushla
 2 years ago
Best ResponseYou've already chosen the best response.1@jenejij take a look http://www.mathsisfun.com/algebra/completingsquare.html

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1Oh okay. I know how to "complete the square" haha. Got it. =)

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1Actually  still having problems.. =/ I don't think x=3. x= 0, and x= 12.

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1x=12 is not right answer

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1thats what the answer in the back of my text book is... but I don't know how to get there.

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1what is the final answer of first part?

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1d = 0 and d= 12. According the the textbook...

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1and for second part ??

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1\[d = + or  2 / \sqrt{13}\]

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1I got the answer: plz check it

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1the value of x coordinate of vertex is given by b/2a; from the given question we have a=1 b=d c=3d substituting the values in b/2a we have d/2

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1to find y ordinate substitute this value in the given eq. we have dw:1341572810912:dw

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1I circled that thing.. is it d?

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1since it has vertex on x axis thus y=0 hence we have d^2/4  d^2/2 +3d = 0 on solving we have d=0 and 12

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1have u understood ??

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1similarly u can do second part .. plz do it and tell me have u got the answer or not

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1give me a medal .........lol

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1\[x^2 + 3dx  d^2 +1 then 0 = (d/2)^2 +3d(d/2)  d^2 + 1 \]

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1\[(d/4)^2 + 3d^2/2 d^2 +1 = 0 \]

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1no; for second part u again need to find the x coordinate and follow the same steps

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1since it was a different equation

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1okay let me try again. toss that grain of salt my way (I've been working all night.. it's 4:21 am) I'm not usually this bad haha

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1no problem: from which country u r from ??

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1okay so then is 3d = b/2a?

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1I can't think. I have to do this in the morning. Thanks so far.

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1give me 1 min, let me tell you

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1in second part : a=1 b=3d c=1 now subs. in b/2a u have 3d/2

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1okay. I was on the right track. but not quite there.

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1then put this value of x in original equation x^2+3dx+1=0dw:1341574077931:dw

jenejij
 2 years ago
Best ResponseYou've already chosen the best response.1Okay. I see the answer. And I understand, but without sleep I won't reeeally get it. Again thank you for your help.

k.rajabhishek
 2 years ago
Best ResponseYou've already chosen the best response.1bye i had sent u mail plz check it
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