Question

x/x-3-6/x+3=72/x^2-9

Answer 1

Vejamos: x/x-3 - 6/x+3 = 72/x^2-9 x/x-3 - 6/x+3 = 72/(x+3).(x-3) x.(x+3)/(x+3).(x-3) - 6.(x-3)/(x+3).(x-3) = 72.1/(x+3).(x-3) x.(x+3) - 6.(x-3) = 72.1 x^2 + 3x - 6x + 18 = 72 x^2 - 3x + 18 - 72 = 0 x^2 - 3x - 54 = 0 a = 1 b = -3 c = -54 ∆ = b^2 - 4ac ∆ = (-3)^2 - 4.1.(-54) ∆ = 9 + 216 ∆ = 225 x = (-b +-√∆)/2a x = (-(-3) +-√225)/2.1 x = (3 +-15)/2 x' = (3 + 15)/2 x' = 18/2 x' = 9 x'' = (3 - 15)/2 x'' = -12/2 x'' = -6 S = {9,-6}