a (x - 1) . ( x + 3 ) = 0
TH1 : x - 1 = 0 TH2 : x + 3 = 0
x = 0 + 1 x = 0 - 3
x = 1 x = - 3
b ( x + 5 ) . ( x2 + 1 ) = 0
TH1 : x + 5 = 0 TH2 : x2 + 1 = 0
x = 0 - 5 x2 = 0 -1
x = - 5 x2 = -1
x2 = - 12
x = -1
c ( x + 2 ) . ( x2 - 9 ) = 0
TH1 : x + 2 = 0 TH2 : x2 - 9 = 0
x = 0 - 2 x2 = 0 + 9
x = - 2 x2 = 9
x2 = 32
x = 3