Given:
-x + y = 2
y = x² - 4
Make y subject of formula in the first equation.
y = x + 2
Substitute into the second equation.
x + 2 = x² - 4
Subtract x+2 from both-side of the equation.
x²- 4 - x - 2 = 0
x² - x - 4 - 2 = 0
x² - x - 6 = 0
Solve for x using factorisation method.
Replace the coefficient of x by two numbers whose product gives -6 and sum gives -1.
That is;
x² - 3x + 2x - 6 = 0
x(x- 3) + 2 ( x - 3) = 0
(x-3)(x+2) = 0
Either x - 3 = 0
⇒x = 3
OR
x + 2 = 0
⇒ x = -2
Therefore, the coordinates of x are -2 and 3.