Question

Help? Solve the system of equations.

y = 3x
y = x2 + 3x – 16
solutions: ( );( )

Answer 1

(- 4, - 12 ) , (4, 12 )

Explanation:

Given the 2 equations

y = 3x → (1)

y = x² + 3x - 16 → (2)

Substitute y = x² + 3x - 16 into (1)

x² + 3x - 16 = 3x ( subtract 3x from both sides )

x² - 16 = 0 ( add 16 to both sides )

x² = 16 ( take the square root of both sides )

x = ±
`√(16)` = ± 4

Substitute these values into (1) for corresponding values of y

x = - 4 : y = 3 × - 4 = - 12 ⇒ (- 4, - 12 )

x = 4 : y = 3 × 4 = 12 ⇒ (4, 12 )