first make an equaiton equal to only 1 variable
1.
x-y=2
add y to both sides
x=y+2
sub
4(y+2)-3y=11
4y+8-3y=11
y+8=11
y=3
sub
x=y+2
x=3+2
x=5
(5,3)
2.
x+2y=7
subtract 2y
x=7-2y
sub
-2(7-2y)+3y=14
-14+4y+3y=14
7y-14=14
7y=28
y=4
sub
x=7-2y
x=7-2(4)
x=7-8
x=-1
(-1,4)
3.
6x-y=-4
subtract 6x
-y=-4-6x
multily -1
y=4+6x
sub
2x+2(4+6x)=15
2x+8+12x=15
14x+8=15
14x=7
x=1/2
sub
y=4+6x
y=4+6(1/2)
y=4+3
y=7
(1/2,7)
1. (5,3)
2. (-1,4)
3. (1/2,7)