Question

$left { {{2x+3 (x+y)=11.} atop {7 (x+3y)-6x=-59.}} right.$

Answer 1

2х+3(х+у)=11
7(х+3у)-6х=-59
--
2х+3х+3у=11
7х+21у-6х=-59
--
5х+3у=11
х+21у=-59
--
5х+3у=11
х=-59-21у
--
5(-59-21у)+3у=11
х=-59-21у
--
-295-105у+3у=11
х=-59-21у
--
-102у=306
х=-59-21у
--
у=306÷(-102)
х=-59-21у
--
у=-3
х=-59-21×(-3)
--
у=-3
х=-59+63
--
у=-3
х=4