Answer:
Step-by-step explanation:
(x +y)² = x² + 2xy +y²
-5(x + 3)² = -80
-5(x² + 2*x*3 + 3²) = -80
-5(x² + 6x + 9) = -80
Divide the equation by (-5)
x² + 6x +9 = -80/-5
x² + 6x + 9 = 16
x² + 6x + 9 - 16 = 0
x² + 6x - 7 = 0
x² - x + 7x - 7 = 0
x(x - 1) + 7(x - 1) = 0
(x - 1)(x + 7) = 0
x -1 = 0 ; x + 7 = 0
x = 1 ; x = -7
