Решите медодом потстановки

{3x+4y=47

{2y-x=1

{2 (x-2y) = x-8y

{5 (x+y) = 2 (x-y) + 10

{2x-4y=x-8y

{5x+5y=2x-2y+10

{2x-4y-x+8y=0

{5x+5y-2x+2y=10

{x+4y=0|*3

{3x+7y=10

-{3x+12y=0

-{3x+7y=10

5y=10|:5

y=2

3x+12*2=0

3x=-24|:3

x=-8

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

{7 (x-5y) + 6x=3 (x+4y) + 27

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

{7x-35y+6x=3x+12y+27

{-x+12y-4x-2y=0

{13x-35y-3x-12y=27

{-5x+10y=0|*2

{10x-47y=27

+{-10x+20y=0

+{10x-47y=27

-27y=27|: (-27)

y=-1

-10x-1*20=0

-10x=20|: (-10)

x=-2

{15+2 (x+3y) = 3 (4x+y)

{2 (5x-y) - 3y=2+3 (2x-y)

{15+2x+6y=12x+3y

{10x-2y-3y=2+6x-3y

{2x+6y-12x-3y=-15

{10x-5y-6x+3y=2

{-10x+3y=-15|*2

{4x-2y=2|*3

+{-20x+6y=-30

+{12x-6y=6

-8x=-24|: (-8)

x=3

12*3-6y=6

-6y=6-36

-6y=-30|: (-6)

y=5

{5 (7x+2y) - 11y=6 (2x+y) + 2 {33+3 (6x-5y) = 3 (x+2y) - 5y

{35x+10y-11y=12x+6y+2

{33+18x-15y=3x+6y-5y

{35x-y-12x-6y=2

{18x-15y-3x-6y+5y=-33

{23x-7y=2|*16

{15x-16y=-33|*7

-{368x-112y=32

-{105x-112y=-231

263x=263|:263

x=1

15*1-16y=-33

-16y=-33-15

-16y=-48|: (-16)

y=3