How to do x2-x-y=11 and x-y=2 doing substitution or elimination.

Question

To determine the solution of the system of equation.

Answer 1

x² - x - y = 11 and x - y = 2

From the second equation, y = x - 2.

Substitute for y in the other equation: x² - x - (x - 2) = 11

So, x² - 2x + 2 = 11

x² - 2x - 9 = 0

Use the quadratic Formula to find x and then use the fact that y = x - 2 to get y.