Question

3x ×(x+1)-x=33-x2+6x-9

Answer 1

3x *(x+1) - x = 33 -x²+ 6x -9

3x² + 3x - x - 33 + x² - 6x + 9 = 0

4x² - 4x - 24 = 0 (:4)

x² - x - 6 = 0 (Báskara)

Δ = b²-4ac = 1 +24 = 25

√Δ= +-√25 = +-5

x' = (1-5)/2 = -2

x" = (1+5)/2 = 3

S = {-2, 3}