Question

Помогите пожалуйста)))))))

Answer 1

$\left \{ {{x+2y=4} \atop {-3x+y=7}} \right. \\ x = 4 - 2y \\ -3 (4-2y) + y = 7 \\ -12+6y+y = 7 \\ 7y = 7+12 \\ 7y = 19 \\ y = \frac{19}{7} \\ x = 4 - 2 * \frac{19}{7} \\ x = 4 - \frac{38}{7} \\ x= \frac{-10}{7}$