Question

Enter your answer and show all the steps that you use to solve this problem in the space provided

Answer 1

Answer: x = -4, x = 5

Step-by-step explanation:

You can use the substitution method for this problem.

y = $x^{2}$ + 2x, but y also = 3x +20.

Because of this, you can determine that $x^{2}$ +2x = 3x + 20 because they are both equal to the same thing, y.

Solve the quadratic equation you got from substitution:

$x^{2}$ + 2x = 3x + 20

$x^{2}$ -x = 20

$x^{2}$ -x -20 = 0

You can factor this equation:

(x+4)(x-5) = 0

x = -4, x = 5