a) {2x-½y=3 {y-4x=-6 {2x-½y=3 /*2 {4x+y=-6 {-4x-y=6 {4x+y=-6 4x=-6 / :4 x =-1½ y-4x=-6 y-4*1½=-6 y-6=-6 /+6 y = 0 b) {x-y=3 /*10 {-5x+10y= -10 {10x-10y=30 {-5x+10y= -10 10x=30 / :10 x=3 x-y=3 3-y=3 /-3 -y=0 / :-1 y=0 c) {6x+y=3 /*-½ {3x+½y=5 {-3x+-½y=-1½ {3x+½y=5 3x=5 /:3 x=1⅔ 3x+½y=5 3*1⅔ + ½y=5 5 + ½y=5 /-5 ½y=0 /:½ y=0 d){x-2y=-4 / * -0,5 {0,5x+y=2 {-0,5x + y=2 {0,5x+y=2 y=2 x-2y=-4 x-2*2=-4 x-4=-4 /+ 4 x=0
a) {2x-½y=3 |*2 {y-4x=-6 {-4x-y=6 {4x+y=-6 4x=-6 / :4 x =-1½ x =-1½ y-4x=-6 x =-1½ y-4*1½=-6 x =-1½ y-6=-6 /+6 x =-1½ y = 0 b) {x-y=3 /*10 {-5x+10y= -10 {10x-10y=30 {-5x+10y= -10 +___________ 5x=20| :5 x=4 x-y=3 4-3=y x=4 y=1 c) {6x+y=3 /*-½ {3x+½y=5 {-3x+-½y=-1½ {3x+½y=5 3x=5 /:3 x=1⅔ 3x+½y=5 3*1⅔ + ½y=5 5 + ½y=5 /-5 ½y=0 /:½ y=0 d){x-2y=-4 / * -0,5 {0,5x+y=2 {-0,5x + y=2 {0,5x+y=2 y=2 x-2y=-4 x-2*2=-4 x-4=-4 /+ 4 x=0 ^^
