How to find the value of a and the value of b?

x^2-16x+a=(x+b)^2x216x+a=(x+b)2

2 Answers
Mar 13, 2017

a=64a=64 and b=-8b=8

Explanation:

This appears to be a way of finding a number aa, which when added to x^2-16xx216x results in a square of form (x+b)^2(x+b)2

We can write x^2-16x+a=(x+b)^2x216x+a=(x+b)2 as

x^2-16x+a=x^2+2bx+b^2x216x+a=x2+2bx+b2

Now comparing coefficients of similar terms

2b=-162b=16 or b=-8b=8

and a=b^2=(-8)^2=64a=b2=(8)2=64

Mar 13, 2017

a=64" "a=64 and " "b=-8 b=8

Explanation:

Given:

x^2-16x+a = (x+b)^2x216x+a=(x+b)2

color(white)(x^2-16x+a) = x^2+2bx+b^2x216x+a=x2+2bx+b2

Equating the coefficients of xx, we find:

-16 = 2b16=2b

Hence:

b = -8b=8

Then:

b^2 = (-8)^2 = 64b2=(8)2=64

So equating the constant terms, we find:

a = 64a=64