Question

x - 7X ao quadrado = 0

Answer 1

x - 7 x² = 0
-7 x² + 1 x = 0
x(-7 x + 1 ) = 0
x = 0
-7 x + 1 = 0
-7 x = -1
x = -1/-7
x = 1/7
S = {0 ; 1/7 }