Select the polynomial that is a perfect square trinomial.
36x2 − 4x + 16
16x2 − 8x + 36
25x2 + 9x + 4
4x2 + 20x + 25

Option D. It's a perfect square trinomial.

Step-by-step explanation:

(a) 36x² - 4x + 16

= (6x)² - 2(2x) + (4)²

It's not a perfect square trinomial

(b) 16x² - 8x + 36

= (4x)² - 2x(4x) + (6)²

It's not a perfect square trinomial

(c) 25x² + 9x + 4

= (5x)² + 2 + (2)²

It's not a perfect square trinomial

(d) 4x² + 20x + 25

= (2x)² + 2(10x) + (5)²

= (2x+5)²

It's a perfect square trinomial.

b.an increase in a causes b to decrease

b.-4 units

all you   do is count how many times you move