y = - 2x and y = x² - 8, this means that:
-2x = x² - 8 → x² + 2x - 8 = 0
Solve this quadratic equation:
x₁ = [-b + √(b² - 4.a.c)]/2a and x₂ = [-b - √(b² - 4.a.c)]/2a
x₁ = [- 2 + √(4+32)]/2 and x₂ = [- 2 - √(4+32)]/2
x₁ = -4 and x₂ = 2 (in the 2nd equation). Now plug in these values in the 1st equation and you will find - 4 and 8
Answer D