Answer:
64
Step-by-step explanation:
The question is incomplete without the expression that would be used to find the constant necessary to make a perfect square trinomial.
I would show you how to find the constant necessary to make a perfect square trinomial using the expression below:
x² - 16x + c
The expression above is in the form of a quadratic: ax² + bx + c
Where a = 1, b = -16, c = constant
First thing we do, is to square half the coefficient of x
Coefficient x above = b = -16
square of half the coefficient of x = (-16/2)²
Expand it, we have = -16/2 × -16/2 = 8×8 = 64
Replace the constant with 64
x² - 16x + 64
b/2 = -16/2 = -8
(x - 8)² will give a perfect square trinomial
Therefore the constant which makes the above expression a perfect square trinomial is 64