Question

Find the roots of f(x)=x2+9x-36.

x = _____ or x = _____

Answer 1

Hi there!

`\large\boxed{x = -12, 3}`

The roots of a function are when f(x) = 0, so:

0 = x² + 9x - 36

Find two numbers that multiply to -36 and add up to 9.

We get the numbers 12 and -3, so:

0 = (x + 12)(x - 3)

Set each equal to 0 to find the x value:

0 = x + 12

x = -12

0 = x - 3

x = 3