(1) -8x-2y=-22, 8x+2y=22, 8(3y-20)+2y=22, 24y-160+2y=22, 26y=182, y=7, x=3y-20=21-20=1. Solution: x=1, y=7.
(2) 3x+2(2x+1)=-5, 3x+4x+2=-5, 7x=-7, x=-1, y=2x+1=-2+1=-1. Solution: x=-1, y=-1.
(3) 7x+5y=22, 21x+15y=66,
+
-3x+2y=-26, -21x+14y=-182
29y=-116, y=-4.
-3x+2y=-3x-8=-26, 3x+8=26, 3x=18, x=6.
Solution: x=6, y=-4.
(4) y=-2x+6=5x-22, 28=7x, x=4; y=-2x+6=-8+6=-2.
Solution: x=4, y=-2.