bonjour
(E1) 12x + 3 = 7x + 8
12 x - 7 x = 8 - 3
5 x= 5
x = 1
(E2) 10x + 7 = 15x - 28
10 x - 15 x = - 28 - 7
- 5 x = - 35
x = 7
(E3) 6x -6 = 3x -3
6 x - 3 x = - 3 + 6
3 x = 3
x = 1
(E4) x² + 3x = 5x
x² + 3 x - 5 x = 0
x² - 2 x = 0
x ( x - 2 ) = 0
x = 0 ou 2
(E5) ( x - 1 )( 2x + 3) + ( x - 1)(3x - 4) = 0
( x - 1 ) ( 2 x + 3 + 3 x - 4 ) = 0
( x - 1 ) ( 5 x - 1 ) = 0
x = 1 ou 1/5
