15x - 8x = 217x = 21x = 21 / 7x = 3
3x - x = 122x = 12x = 12 / 2x = 6
2x + 4x = 306x = 30x = 30 / 6x = 5
x + 8x = 729x = 72x = 72 / 9x = 8
4y + 2y - y = 205y = 20y = 20 / 5y = 4
9x + x - 9x = 5x = 5
7y + y - 2y = 246y = 24y = 24 / 6y = 4
4x + 3x - 7x = 6x = 6
15x - 8x = 21
7x = 21
x = 21 / 7
x = 3
3x - x = 12
2x = 12
x = 12 / 2
x = 6
2x + 4x = 30
6x = 30
x = 30 / 6
x = 5
x + 8x = 72
9x = 72
x = 72 / 9
x = 8
4y + 2y - y = 20
5y = 20
y = 20 / 5
y = 4
9x + x - 9x = 5
x = 5
7y + y - 2y = 24
6y = 24
y = 24 / 6
y = 4
4x + 3x - 7x = 6
x = 6