Question

Which of the following uses the substitution method to solve linear-quadratic system y = x^2 - 4x + 8, y = 3x - 4? (1 point)

Answer 1

Substitute y = 3x − 4 into y = x^2 − 4x + 8:

x^2 − 4x + 8 = 3x − 4
x^2 − 7x + 12 = 0
(x − 3)(x − 4) = 0 → x = 3 or x = 4

Find y from y = 3x − 4:
x = 3 → y = 5
x = 4 → y = 8

Solutions: (3, 5) and (4, 8).