Решите систему уравнений:

1) 3x+7y=-4

5x-8y=13;

2) 4x-5y=12

6x+11y=-19;

3) 2x+9y-2=0

8x-15y-25=0;

1) 3x+7y=-4/*8⇒24x+56y=-32

5x-8y=13/*7⇒35x-56y=91

59x=59

x=1

3+7y=-4

7y=-7

y=-1

(1; -1)

2) 4x-5y=12/11⇒44x-55y=132

6x+11y=-19/*5⇒30x+55y=-95

74x=37

y=0,5

4x-2,5=12

4x=14,5

x=3,625

(3,625; 0,5)

3) 2x+9y-2=0/*-4⇒-8x-36y+8=0

8x-15y-25=0

-51y-17=0

-51y=17

y=-1/3

2x-3-2=0

2x=5

x=2,5

(2,5; -1/3)