Ответ:

a.x=-2

y=4

b.x=18

y=6

Объяснение:

a.5(2x-3y)+7y=-52

2(3x+4y)-6y=-4

10x-8y=-52

6x+2y=-4

10x=8y-52

6x+2y=-4

x=(4y)/5-26/5

6x+2y=-4

x=(4y)/5-26/5

6((4y)/5-26/5)+2y=-4

x=(4y)/5-26/5

(34y)/5-156/5=-4

x=(4y)/5-26/5

(34y)/5=136/5

x=(4y)/5-26/5

y=4

x=-2

y=4

b.(x+y)/2-(x-y)/3=8

(x+y)/3+(x-y)/4=11

x/6+(5y)/6=8

(7x)/12+y/12=11

x/6=1/6(48-5y)

(7x)/12+y/12=11

x=48-5y

(7x)/12+y/12=11

x=48-5y

(7(48-5y))/12+y/12=11

x=48-5y

28-(17y)/6=11

x=48-5y

-(17y)/6=-17

x=48-5y

y=6

x=18

y=6