Question

Determine which polynomial is a perfect square trinomial.

25x2 − 40x − 16
9a2 − 20a − 25
25b2 − 15b + 9
16x2 − 56x + 49

Answer 1

`\it 16x^2-56x+49 = 4^2x^2-56x+7^2=(4x-7)^2`

Answer 2

D) 16x^2 − 56x + 49

Explanation:

It is 16x^2 - 56x + 49

(4x)^2 - 2*4x*7 + 7^2

This is in the form of (a - b)^2 = a^2 - 2ab + b^2

Here a = 4x and b = 7

(4x)^2 - 2*4x*7 + 7^2 = (4x - 7)^2

Therefore, answer is D) 16x^2 − 56x + 49

Hope this will helpful.

Thank you.