3.1.25 Даю 39 б......
У=11+2х 3(х-1)+ 2у=12 3х-3+2у=12 у=11+2х 3х+2у=15 у=11+2х 3х+2(11+2х)=15 3х+22+4х=15 7х=-7 х=-1 у=11+ 2*(-1) у=9