27х+38х+35х=27×28+38×28+35×28=756+1064+980=2800
2. 49y+132y-31y= 49×24+132×24-31×24=1176+3168-744=4344-744=3600
Или же можно так:
27х+38х+35х=100х
100×28=2800
49у+132у-31у=150у
150×24=3600
27х+38х+35х=27×28+38×28+35×28=756+1064+980=2800
2. 49y+132y-31y= 49×24+132×24-31×24=1176+3168-744=4344-744=3600