Thread: find values of A and B

hi,
i need to find the values of A and B to this question:

given that x^2 +12x +A ≡ (x+B)^2

Find values of A and B.

im unsure what to do because before i did:
(x+6) (x+6)
= x^2+12+36

A=36 B=6

however it was wrong so i need to know where i am going wrong and how i get it correct!

help would be great!

thanks!

You have the correct solution, are you sure this is the exact wording/equation?

Originally Posted by andyboy179

given that x^2 +12x +A ≡ (x+B)^2
Find values of A and B.
A=36 B=6
however it was wrong

How do you know that your answer is incorrect?
Are you given a proposed answer?

yes! my teacher wrote in my book "How?" "did you understand it?" "ask me"

but i can't see how im wrong because im sure its correct, that why i asked here so i could know where im going wrong!

Originally Posted by Plato

How do you know that your answer is incorrect?
Are you given a proposed answer?

my book had been marked, see above post to she what she wrote!

Originally Posted by andyboy179

yes! my teacher wrote in my book "How?" "did you understand it?" "ask me"

but i can't see how im wrong because im sure its correct, that why i asked here so i could know where im going wrong!

Originally Posted by andyboy179

my book had been marked, see above post to she what she wrote!

She isn't saying that you're wrong. She is saying that your method is concerning because it looks like you've randomly guessed.

Start the problem from scratch and try to solve it this way: expand the brackets on the right hand side, and then equate the coefficients.

i know what to do now, thanks for clearing that up!!

Originally Posted by andyboy179

hi,
i need to find the values of A and B to this question:

given that x^2 +12x +A ≡ (x+B)^2

Find values of A and B.

It's a little late, but I would propose an altered problem statement:

Given that x^2 +12x +A = (x+B)^2 is satisfied for all x find values of A and B.

Otherwise this problem has an infinite number of solutions for A and B.

-Dan