7y+9-5y=137y-5y=13-92y=4y=2;5y-72=48-3y5y+3y=48+728y=120y=15;11x+42-2x+9x=100-2211x-2x+9x=100-22-4218x=36x=2
7y+9-5y=13
7y-5y=13-9
2y=4
y=2;
5y-72=48-3y
5y+3y=48+72
8y=120
y=15;
11x+42-2x+9x=100-22
11x-2x+9x=100-22-42
18x=36
x=2