1) 4x-y=20
4x=12-y
12-y-y=20
y=-4
4x=12-(-4)
x=4
(x,y)= (4, -4)
2) 17y=52-9x
26x-17y=18
26x-(52-9x)=18 26×2-17y=18
x=2 y=2
3) 7y=2+5x
8x+7y=15
8x+2+5x=15 8×1+7y=15
x=1 y=1
4) 9x=24+6y
9x+8y=10
24+6y+8y=10 9x+8×(-1)=10
y=-1 x=2
1) 4x-y=20
4x=12-y
12-y-y=20
y=-4
4x=12-(-4)
x=4
(x,y)= (4, -4)
2) 17y=52-9x
26x-17y=18
26x-(52-9x)=18 26×2-17y=18
x=2 y=2
3) 7y=2+5x
8x+7y=15
8x+2+5x=15 8×1+7y=15
x=1 y=1
4) 9x=24+6y
9x+8y=10
24+6y+8y=10 9x+8×(-1)=10
y=-1 x=2