Question

Resolva as equações:

a) x² + 13x = 0

b) 2x² + 10x = 0

c) 4x² + 12x = 0

d) x² - 25x = 0

Answer 1

a) x² + 13x = 0    =>
    x(x + 13) = 0   =>
    x = 0
      ou
    x + 13 = 0   =>   x = -13

b)2x² + 10x = 0    =>
   x(2x + 10) = 0   =>
   x = 0
     ou
   2x + 10 = 0   =>   2x = -10   =>   x = -5

c)4x² + 12x = 0    =>
   x(4x + 12) = 0   =>
   x = 0
     ou
   4x + 12 = 0   =>   4x = -12   =>   x = -3

d)x² - 25x = 0    =>
   x(x - 25) = 0   =>
   x = 0 
     ou
   x - 25 = 0   =>   x = 25