Question

Help me solve these equations

Answer 1

`\left\{\begin{array}{ccc}3x-7y=20&|\cdot10\\11x+10y=5&|\cdot7\end{array}\right\\\underline{+\left\{\begin{array}{ccc}30x-70y=200\\77x+70y=35\end{array}\right}\ \ \ \ |\text{add both sides of the equations}\\\\.\ \ \ \ \ 107x=235\ \ \ \ |:107\\.\ \ \ \ \ \ \ \ \ \ x=(235)/(107)\\\\\text{substitute the value of x to the second equation}\\\\11\cdot(235)/(107)+10y=5\\\\(2585)/(107)+10y=(535)/(107)\ \ \ \ |-(2585)/(107)\\\\10y=-(2050)/(107)\ \ \ \ |:10\\\\y=-(205)/(107)`

`Answer:\ x=(235)/(107),\ y=-(205)/(107)`