Answer: x=-2
Y= -20
Explanation
You replace the y in the second equation with 10x. This is because it says 10x=y
2x+10x=12x so you put that
12x=-24
To get x by its self you divide by 12.
-24 divided by 12 is -2.
Now you plug in -2 to either equation as y. I chose the first one because it's easier.
10(-2)=y
-20=y