Answer
The solution of this system is
$$x=3,\qquad y=2.$$
Work Step by Step
We will do this by following the steps below:
Step 1: Subtract from the second equation the first one multiplied by $2$:
$$2x-2x+y-2\times2y=8-2\times7$$ which becomes $$-3y=-6$$ and this gives
$$y=2.$$
Step 2: Use the back substitution $y=2$ into the fist equation and find $x$:
$$x+2\times2=7\Rightarrow x+4=7$$
and this gives
$$x=3.$$