first one
eliminate q's
multiply 2nd equation by -1 and add to 2nd
5p-3q=-39
2p+3q=-3 +
7p+0q=-42
7p=-42
divide both sides by 7
p=-6
sub back
-2p-3q=3
-2(-6)-3q=3
12-3q=3
minus 12
-3q=-9
divide -3
q=3
p=-6
q=3
2nd one
eliminate y's
multiply first equation by -1 and add to 2nd
-4x+3y=-12
7x-3y=3 +
3x+0y=-9
3x=-9
divide both sides by 3
x=-3
sub back
4x-3y=12
4(-3)-3y=12
-12-3y=12
-3y=24
y=-8
(x,y)
(3,-8)
