Hej!
2x + 9 = 1
2x = 1 - 9
2x = -8 || : 2
x = -4
7x - 9 = 5
7x = 5 + 9
7x = 14 || : 7
x = 2
8x + 5 = -7
8x = -7 - 5
8x = -12 || : 8
x = -1,5
7x - 5 = 6x + 8
7x - 6x = 8 + 5
x = 13
5x - 8 = 4x + 9
5x - 4x = 9 + 8
x = 17
9x - 4 = 8x + 5
9x - 8x = 5 + 4
x = 9