Помогите мне (буду очень признателен)!!!!

Решите задачу:

$1)\; \; \left\{\begin{array}{l}x+2y=5|\cdot 2\\-2x+7y=-2\end{array}\right\; \oplus \; \left\{\begin{array}{l}x=5-2y\\11y=8\end{array}\right\; \; \left\{\begin{array}{l}x=\frac{39}{11}\\\; y=\frac{8}{11}\end{array}\right\\\\\\2)\; \; \left\{\begin{array}{l}x-y=4|\cdot 2\\3x+2y=1\end{array}\right\; \oplus \; \left\{\begin{array}{l}y=x-4\\5x=9\end{array}\right\; \; \left\{\begin{array}{l}y=-2,2\\x=1,8\end{array}\right$

$3)\; \; \left\{\begin{array}{l}5x-2y=3|\cdot 3\\3x+6y=2\end{array}\right\; \oplus\; \left\{\begin{array}{l}2y=5x-3\\18x=11\end{array}\right\; \; \left\{\begin{array}{ccc}2y=\frac{1}{18}\\x=\frac{11}{18}\end{array}\right\; \left\{\begin{array}{l}\; y=\frac{1}{36}\\x=\frac{11}{18}\end{array}\right$

$4)\; \; \left\{\begin{array}{l}x-y=-10|\cdot 3\\2x+3y=15\end{array}\right\; \oplus \; \left\{\begin{array}{l}y=x+10\\5x=-15\end{array}\right\; \; \left\{\begin{array}{l}y=7\\x=-3\end{array}\right$

$5)\; \; \left\{\begin{array}{l}6m+5n=1\\2m-7n=9|\cdot (-3)\end{array}\right\; \oplus \; \left\{\begin{array}{l}6m=1-5n\\26n=-26\end{array}\right\; \; \left\{\begin{array}{l}6m=6\\n=-1\end{array}\right\; \left\{\begin{array}{l}m=1\\n=-1\end{array}\right$