Explications étape par étape
x² - 4 = 0
x = 2 ou x = - 2
x ( x - 4 ) = 0
x = 0 ou x = 4
2 ( x + 3 )( 2x - 1 ) = 0
x = - 3 ou x = 1/2
( 2 - x )( x + 5 )( x - 1 ) = 0
x = 2 ; x = - 5 ou x = 1
x² - 2x + 1 = 0
x = 1
