5x+y=7,3x-y=1=>x=1,y=2
4x-3y=5,4x+6y=14=>x=2,y=1
6x+7y=5,6x-7y=19=>=2,y=-1
0.5x-3y=-1,-1/2x+5y=3=>x=4,y=1
3x-2y=6,2x+3y=17=>x=4,y=3
4x-2y=14,5x+y=7 =>x=2,y=-3
x-3y=-20,3x+7y=100=>x=10,y=10
2x-3y=8,5y-7x=5=>x=-5,y=-6
x-3y=2,2x+y=18=>x=8,y=2
2a+b=0,4a+3b=6=>a=-3,b=6
x-3y+20=0,3x-7y-100=0=>x=220,y=80
2y-8=-x,4x+3y=7 =>x=-2,y=5