Question

Suppose we have two equations and they are both equal to each other. Equation A is "y = x^2 - 9" and Equation B is "y = x + 3". If we had to solve this system of equations, what quadratic equation do we have to solve in order to get our x values?

a. x^2 - x - 12 = 0
b. x^2 + x + 3 = 0
c. x^2 - x - 6 = 0

Answer 1

a) x² - x - 12 = 0

Explanation:

We have equation A = equation B

⇒ x² - 9 = x + 3

⇒ x² - 9 - x - 3 = 0

⇒ x² - x - 12 = 0