Answer:
16x^2 + 24x + 9
Explanation:
perfect square trinomial is of the form
a^2 + 2 * a * b + b^2
9x^2 + 9x + 1 = (3x)^2 + 3*3x*1 + 1^2 not a perfect square trinomial
36b^2 − 24b + 8 = ( 6b)^2 -2 * 6b *2 + ( 2 sqrt(2)) ^2 not a perfect square trinomial
16x^2 + 24x + 9 = ( 4x) ^2 + 2 * ( 4x) * 3 + 3^2 = perfect square trinomial
4a^2 − 10a + 25 = ( 2a) ^2 - 1 * 2a *5 + 5^2 not a perfect square trinomial