Which ones are perfect square trinomials?
a is do you know how i figured that out?
No, I don't.
have you learned foil?
No A is not the right answer!
Diya, there is more than one I can choose for the right answer. How come A isn't one of them?
|dw:1338062447129:dw| that is y it is
If \( ax^2+bx+c \) is a perfect square trinomial then the discriminant will be zero. Do you know to find the discriminant? \( D= b^2- 4ac =0\)
I'm so confused...
thats not how you do that
noo it equals a
um.. Can someone just show me how to do these or.. if you are going to argue.. just give me a hint to the right answers please...
are you in algebra 1?
for the 3rd time.
@careless850 Lets check the second option \( 4a^2 − 20a + 25 \) this is of the form \( ax^2+ bx + c \) Now find \(b^2-4ac \) \(b^2-4ac = (-20)^2- 4*4*25= 400-400 = 0 \) Now verify if your answer is right \( 4a^2 − 20a + 25 = (5-2a)(5-2a) =(5-2a)^2 \)
ok thanks its and b :) because you can divide the first one and last one by a number and get the same number you divided by and get a whole number
O.o what? So is one of the answers A or is one B?
the 2 answers are a and b because if you factor them you don't get more that 2 numbers like the one i showed you above earlier
So C and D aren't?
\( 49x^2 − 8x + 16 \) Find \(b^2 -4ac \) b=-8 , a=49 , c=16 \(b^2 -4ac = (-8)^2 - 4(49)(16) = -3120 \) So option A is not the right answer Can you check for C now?
Diya, A isn't right? So the only right answer is B?
A isn't Right! i just showed you why.. B is right But you have to check the others too
you can have more than one right answer right? if so its a and b
Nope, try to solve it and see
There is multiple answers that can be right.
Can you find the discriminant of C & D ? \( D= b^2-4ac \)
I don't know what the disciminant is.
\( 25b^2 − 5b + 10\) this is of the form \( ax^2 + bx +c \) |dw:1338063436660:dw| so a =25 b=-5 c=10 Now find Dicriminant \( D =b^2-4*a*c\) Can you do that?
Just plug in the values of a ,b & c in the equation \(b^2 - 4ac \) can you ?
is it equal to zero or some other number ?
I'm still confused..
where are you stuck ? did you find b^2 -4ac?
Find it :) & check if its equal to zero
How do I find it?
25b^2 − 5b + 10 Given : a =25 b=-5 c=10 b^2 - 4ac
(-5)^2 - 4* 25 * 10 is it equal to zero?
so its not a perfect square trinomial Now do the last one D) 16x^2 − 8x + 1 Can you tell me what is a ,b & c here?
a is 16
yes b & c?
-8 is b and 1 is c.
Right!!!!!!! Now Find the discriminant How do you find it?
So I would do this.. -> -8^2 -4*16*1.
Yessss good work :)
how to solve that, I don't know, but that's the problem.. lol
\( (8)^2 - 4 \times 16 \times 1 \) What is \( 8^2 \) ?
64-64 = 0
So it's a PST
Yess!! so its a perfect square trinomial :) You can verify by factoring ^_^
I see. Pretty easy now I guess. So the only ones that are perfect square trinomials are B and D?
Can you help me with another?
Yes, If you factorise 16x^2 − 8x + 1 you'll get (1-4x)(1-4x) = (1-4x)^2 Post it as a new question :)
Yes its B & D
Thank you. :))