Решить систему уравнения 1)2•(3x+2y)+9=4x+21 3-(6x+5y)=2x+10 2)2•(3x-y)-5=2x-3y...

Решите задачу:

$\left \{{{2(3x+2y)+9=4x+21} \atop {3-(6x+5y)=2x+10}} \right. \\ \\ \left \{{{6x+4y+9=4x+21} \atop {3-6x-5y=2x+10}} \right. \\ \\ \left \{{{2x+4y=12} \atop {-8x-5y=7}} \right. \\ \\ \left \{{{x+2y=6} \atop {-8x-5y=7}} \right. \\ \\ \left \{{{x=6-2y} \atop {-8x-5y=7}} \right. \\ \\ -8(6-2y)-5y=7 \\ -48+16y-5y=7 \\ 11y=55 \\ y=5 \\ \\ x=6-2*5=6-10=-4$

$\left \{{{2(3x-y)-5=2x-3y} \atop {5-(x-2y)=4y+16}} \right. \\ \\ \left \{{{6x-2y-5=2x-3y} \atop {5-x+2y=4y+16}} \right. \\ \\ \left \{{{4x+y=5} \atop {-x-2y=11}} \right. \\ \\ \left \{{{y=5-4x} \atop {-x-2y=11}} \right. \\ \\ -x-2(5-4x)=11 \\ -x-10+8x=11 \\ 7x=21 \\ x=3 \\ \\ y=5-4*3=5-12=-7$