Question

What value of c makes x^2 - 24x + c a perfect square trinomial?

Answer 1

Divide 24 by two and square it
The answer is 144

Answer 2

Explanation:

Quadratic equation is given by x²-24x+c

This is in the form expansion of (a-b)², that is a²-2ab+b²

Comparing

a² = x², a = x

-2ab = -24x

-2xb = -24x

b = 12

c = b² = 12² =144

x²-24x+144 = (x-12)²

Option D is the correct answer