7x+21=3y+1
8-4x=5y+5+1
7x-3y= -20
-4x-5y= -2
35x-15y=-100
12x+15y=6
47x= -94
x=-2
y= (-7*2+20)/3= 2
ответ:(-2;2)
{7(х+3)=3у+1
{4(2-х)=5(у+1)+1
.
{7х+21=3у+1
{8-4х=5у+5+1
.
{7х-3у=-20 | ×5
{4х+5у=2 |×3
.
{35х-15у=-100
{12х+15у=6
.
47х=-94
х=-2
.
7×(-2)-3у=-20
-14-3у=-20
3у=6
у=2
.
ответ: (-2; 2)
