1)8x-3y=19
7x+y=13
8x-3y=19
y=13-7x
8x-3(13-7x)=19
y=13-7x
8x-39+21x=19
y=13-7x
29x=58
y=13-7x
x=2
y=13-7*2
x=2
y=-1
2)x+9y=22
6x+5y=34
x=22-9y
6(22-9y)+5y=34
x=22-9y
132-54y+5y=34
x=22-9y
-49y=-98
x=22-9y
y=2
x=22-9*2
y=2
x=4
y=2
3)7x-5y=19
2x+y=3
7x-5y=19
y=3-2x
7x-5(3-2x)=19
y=3-2x
7x-15+10x=19
y=3-2x
17x=34
y=3-2x
x=2
y=3-2*2
x=2
y=-1
4)x+2y=2
3x+7y=9
x=2-2y
3(2-2y)+7y=9
x=2-2y
6-6y+7y=9
x=2-2y
y=3
x=2-2*3
y=-3