2(3х+2у)+9=4х+21
2х+10=3-(6х+5у)
2(3х+2у)+9=4х+21
2х+10=3-6х-5у
8х=-5у-7
2(3х+2у)+9=4х+21
х=-0,625у-0,875
6х+4у+9=4х+21
х=-0,625у-0,875
2х + 4у=12
х=-0,625у-0,875
2(-0,625у-0,875) + 4у=12
х=-0,625у-0,875
-1,25у +4у =12+ 1,75
х=-0,625у-0,875
2,75у= 13,75
у= 5
х= -0,625*5-0,875
у=5
х=-4
ответ: (-4;5)
1) 2(3х+2у)+9=4х+21
6x + 4y + 9 - 4x - 21= 0
2x+ 4y - 12 = 0
2(x+2y-6) = 0
x + 2y - 6 = 0
x + 2y = 6
2) 2х+10=3-(6х+5у)
2х + 10 - 3 + 6х + 5у = 0
8x + 5y +7 = 0
8x + 5y = -7
x + 2y = 6 \*(-8)
8x + 5y = -7
-8x - 16y = -48
8x + 5y = -7
-11y = -55
y = 5
