Question

Como resolver (x - 4) . (x + 5) = 0

Answer 1

( x - 4 ) . ( x + 5 ) = 0

x2 - 4x . x2 + 20 =0

x2 - x2 -4x = -20

4x = -20

Answer 2

(x-4) × (x+5)=0
x^2+5x-4x-20=0
x^2=-5x+4x+20
x^2=-1+20
x^2=19/1
x=19