Question

Решить систему уравнения
1)2•(3x+2y)+9=4x+21
3-(6x+5y)=2x+10
2)2•(3x-y)-5=2x-3y
5-(x-2y)=4y+16

Answer 1

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

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