1){12х+16у+1=0,
{3х-4у+2=0
{12х+16у=-1
{3х-4у=-2|*(-4)
{12х+16у=-1
{-12х+16у=8
12х+16у+(-12х)+16у=-1+8
12х+16у-12х+16у=7
32у=7|:32
у=7/32
3х-4*(7/32)=-2|*32
96х-28=-64
96х=-64+28
96х=-36|:96
х=-36/96=-3/8
Ответ:(7/32;(-3/8))
2){3у-4х+6=0
{5х-9у+10=0
{-4х+3у=-6|*3
{5х-9у=-10
{-12х+9у=-18
{5х-9у=-10
-12х+9у+5х+(-9у)=-18+(-10)
-12х+9у+5х-9у=-18-10=-28
-7х=-28|:(-7)
х=4
5*4-9у=-10
20-9у=-10
-9у=-10-20
-9у=-30|:(-9)
у=30/9=3(3/9)=3(1/3)
Ответ: (4;3(1/3))