Question

equaçao de 2ºgrau
(x-4)(x-5)=20

Answer 1

(x-4)(x-5)=20

x² - 5x - 4x + 20 = 20

x² - 5x - 4x + 20 - 20  = 0
x² - 9x  = 0

eq.incompleta

x(x-9) = 0

x1 = 0

x2 - 9 = 0
  x2 = 9

Answer 2

-> x²-5x-4x+20=20
x²-9x=20-20
x²-9x=0
x(x-9)=0
x=0
                                                                        S=0;9
-> x-9=0
x=9