Question

What value of 'a' would make the expression a perfect square?
x^2 + 12x-a​

Answer 1

a = -36

Explanation:

Here, we want to get the value of a that would make the expression a perfect square

we simply divide the coefficient of x by 2

That would give 12/2 = 6

Now, square this = 6^2 = 36

Since the number we are to add will be positive so we can have a perfect square of the measure (x + 6)^2;

Then a has to be negative for the last number to turn out positive

Thus, a = -36