50 графическим систему: 1) { х+у=0 {3х+2у=-2; 2) {х+у=7, {-х+2у=-4; 3) { х+2у=4, {-1,5х+у=6; 4) {х-у=-2, {5х-2у=2.

1.
x=-y
3x-2y=-2

-3y-2y=-2
-5y=-2
y=0.4
x=-0.4

2.
x+y=7
+
-x+2y=-4

y+2y=3
y=1
x=7-2y=5

3.
x+2y=4
-1.5x+y=6 |2

x=4-2y
-3x+2y=12

2y-12+2y=12
y=6
x=-8

4.
x-y=-2
5x-2y=2

x=-2+y
5y-10-2y=2
3y=12
y=4
x=2