Answer:
A
Step-by-step explanation:
y = - 2x + 5 → (1)
y = x² + 3x + 9 → (2)
substitute y = x² + 3x + 9 into (1)
x² + 3x + 9 = - 2x + 5 ( subtract - 2x + 5 from both sides )
x² + 5x + 4 = 0 ← in standard form
(x + 1)(x + 4) = 0 ← in factored form
equate each factor to zero and solve for x
x + 1 = 0 ⇒ x = - 1
x + 4 = 0 ⇒ x = - 4
substitute these values into (1) for corresponding values of y
x = - 1 : y = - 2(- 1) + 5 = 2 + 5 = 7 ⇒ (- 1, 7 )
x = - 4 : y = - 2(- 4) + 5 = 8 + 5 = 13 ⇒ (- 4, 13 )
