{2х+3(х+у)=11 решите систему уравнений {7(х+3у)-4у=-23

{2х+3(х+у)=11,  {2х+3х+3у=11,  {5х+3у=11,    {5х=11-3у,    {х=11-3у/5,
{7(х+3у)-4у=-23,{7х+21у-4у=-23, {7х+17у=-23,{7х+17у=-23,{7х+17у=-23,
{х=11-3у/5,            {х=11-3у/5,                {х=11-3у/5,
{7*11-3у/5+17у=-23,{35(11-3у)+85у=-115, {385-105у+85у=-115,
{х=11-3у/5, {11-3*25/5, {х=12,8,
{20у=500,  {у=25,        {у=25.