Question

Решите пожалуйста систему способом подстановки отдам 10 баллов....

Answer 1

$\left \{ {{\frac{1}{5}(3x+4y)=11 }|*5 \atop {\frac{1}{4}(7x-y)=14 }|*4} \right.\\\\\left \{ {{3x+4y=55} \atop {7x-y=56}} \right.\\\\\left \{ {{3x+4(7x-56)=55} \atop {y=7x-56}} \right.\\\\\left \{ {{3x+28x-224=55} \atop {y=7x-56}} \right.\\\\\left \{ {{31x=279} \atop {y=7x-56}} \right.\\\\\left \{ {{x=9} \atop {y=7*9-56}} \right.\\\\\left \{ {{x=9} \atop {y=7}} \right. \\\\Otvet:\boxed{(9 \ ; \ 7)}$

Answer 2

Ответ смотри на фотографии