{2(3x+2y)+9=4x+21 {2x+10=3-(6x+5y)​

{2(3х+2y)+9=4x+21, → 6x+4y+9=4x+21

{2x+10=3-(6x+5y).→↓ 6x+4y-4x=21-9

2x+4y=12 |÷2

x + 2y = 6 ;

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

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

8x + 5y = - 7 ;

↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓ ↓

{x+2y=6 |*(-8), →{-8x-16y=-48

{8x+5y=-7. →{8x+5y=-7.

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x+2*5=6 - 11y = -55

x + 10 = 6 y = 5 ;

x = 6 - 10

x === - 4