ex 61
a 3x + 5 + 4x -2= 8x +3
b 10x + 3 - 4x - 8 = 6x -5
c - 9x + 1 + 4 - 5x = - 14x +5
d x - 7 - 4 x + 3 = 5x -4
ex 62
1 ) a A + B =8x -6 -5x + 4 = 3x - 1
b A - B = 8x - 6 +5x - 4 =13 x - 10
c 2A + 3 B = 2 (8x -6 ) + 3(-5x + 4) = 16x -12 -15x + 12 = x
d 5A - 3B = 5(8x -6 ) -3 (-5x + 4) = 40x - 30 +15x - 12=55x -42
2 ) 2( A+B)
méthode 1
2 [ (8x - 6 ) + (-5x + 4)] = 2 (8x - 6 - 5x + 4 )= 2 (3x -2) = 6x -4
méthode 2
2 (8x -6) + 2 (-5x + 4 ) = 16x - 12 -10 x + 8 = 6 x -4
