Question

решите систему ур-ий методом подстановки (20 баллов!!!!)
у-2х=1
6х-у=7
_____
х = 2 – у,
3х – 2у = 11
_____
х + у = 6,
3х – 5у = 2.

Answer 1

$1) \left { {{y-2x=1} atop {6x-y=7}} right. \ left { {{y=1+2x} atop {6x-(1+2x)=7}} right. \ left { {{y=1-2x} atop {4x=8}} right. \ left { {{y=1-2x} atop {x=2}} right. \ left { {{y=5} atop {x=2}} right. \ 2) \ left { {{x=2-y} atop {3x-2y=11}} right. \ left { {{x=2-y} atop {3(2-y)-2y=11}} right. \ left { {{x=2-y} atop {y=-1}} right. \ left { {{x=3} atop {y=-1}} right.$
$3) \ left { {{x+y=6} atop {3x-5y=2}} right. \ left { {{y=6-x} atop {3x-5(6-x)=2}} right. \ left { {{y=6-x} atop {8x=32}} right. \ left { {{y=6-x} atop {x=4}} right. \ left { {{y=2} atop {x=4}} right.$