Question

Which polynomial is a perfect square trinomial?

25x2 − 20x − 16
9a2 − 30a − 25
25b2 − 15b + 9
16x2 − 24x + 9

Answer 1

It is 16x2-24x+9
So...you can put it into the form a2+2ab+b2=(a+b)^2

Answer 2

16x² - 24x + 9 is a perfect square trinomial.

Explanation:

A quadratic polynomial ax²+bx+c is a perfect square trinomial,

If b² = 4ac,

In 25x² - 20x - 16,

(20)² ≠ 4 × 25 × -16

Thus, 25x² - 20x - 16 is not a perfect square trinomial,

In 9x² - 30x - 25,

(-30)² ≠ 4 × 9 × -25

Thus, 9x² - 30x - 25 is not a perfect square trinomial,

In 25b² - 15b + 9,

(-15)² ≠ 4 × 25 × 9

Thus, 25b² - 15b + 9 is not a perfect square trinomial,

In 16x² - 24x + 9,

(-24)²= 4 × 9 × 16

Thus, 16x² - 24x + 9 is a perfect square trinomial.