Bonsoir,
3(2 - 7x) = 4 - (2x + 1)
6 - 21x = 4 - 2x - 1
6 - 3 = 21x - 2x
3 = 19x
x = 3/19
3(2x - 1) - (x + 7) = 0
6x - 3 - x - 7 = 0
5x - 10 = 0
5x = 10
x = 10/5
x = 2
4 + (2x + 1)/2 = x/4 - 1/2
16 + 2(2x + 1) = x - 2
4x + 2 - x = - 2 - 16
3x = -20
x = -20/3
9 - (2x + 7)/3 = 4x/6 - 1/3
54 - 6(2x + 7) = 4x - 2
54 - 42 + 2 = 12x + 4x
14 = 16x
x = 14/16
x = 7/8