Hello.
First off, you can factor this equation to find the missing x-intercept.
y = x² + 8x + 12
y = (x + 6)(x + 2)
Then, you can use the zero product property to find the x values.
x + 6 = 0 x + 2 = 0
- 6 - 6 - 2 - 2
x = -6 x = -2
As an ordered pair: (-6, 0) and (-2, 0)
Thus, your answer is x = -6, -2.
