Помогите через 30 минут надо сдать!!! Дам 35 баллов!

Решите задачу:

$1)\; \; \left\{\begin{array}{l}x-y=-3\; |\cdot 3\\4x+3y=2\end{array}\right\; \oplus \; \left\{\begin{array}{l}y=x+3\\7x=-7\end{array}\right\; \; \left\{\begin{array}{l}y=2\\x=-1\end{array}\right\; \; \; (-1;2)$

$2)\; \; \left\{\begin{array}{l}x-y=2\; |\cdot (-5)\\5x-3y=8\end{array}\right\; \oplus \; \left\{\begin{array}{l}x=y+2\\2y=-2\end{array}\right\; \; \left\{\begin{array}{l}x=1\\y=-1\end{array}\right\; \; \; (1;-1)$

$3)\; \; \left\{\begin{array}{l}7x-3y=13\\-7x-9y=11\end{array}\right\; \oplus \; \left\{\begin{array}{l}7x=3y+13\\-12y=24\end{array}\right\; \; \left\{\begin{array}{l}7x=7\\y=-2\end{array}\right\\\\\\\left\{\begin{array}{l}x=1\\y=-2\end{array}\right\; \; \; (1;-2)$

$4)\; \; \left\{\begin{array}{l}3x+13y=37\\2x-13y=3\end{array}\right\; \oplus \; \left\{\begin{array}{l}13y=-3x+37\\5x=40\end{array}\right\; \; \left\{\begin{array}{}13y=13\\x=8\end{array}\right\\\\\\\left\{\begin{array}{l}y=1\\x=8\end{array}\right\; \; \; (8;1)$