Question

помогите решить способом подстановки!!!!!!!​

Answer 1

2х+7у=11

4х-у=7

х=11-7у:2

4(11-7у):2-у=7

22-14у-у=7

-15у=-15

у=1

х=2

Answer 2

$\displaystyle\left \{ {{2x+7y=11} \atop {4x-y=7}} \right. \\\\\\\displaystyle\left \{ {{2x+7\cdot(4x-7)=11} \atop {y=4x-7}} \right.\\\\\\\displaystyle\left \{ {{2x+28x-49=11} \atop {y=4x-7}} \right.\\\\\\\displaystyle\left \{ {{30x=60} \atop {y=4x-7}} \right.\\\\\\\displaystyle\left \{ {{x=2} \atop {y=4\cdot 2-7}} \right.\\\\\\\displaystyle\left \{ {{x=2} \atop {y=1}} \right.\\\\\\Otvet:\boxed{(2 \ ; \ 1)}$