let's devide the left equation by -1/2 to get it into a form that starts with y=...
y=-x-10
the right equation is
y=2x+2
since y=y the following must also be true (for the point where the two lines intersect):
-x-10=2x+2
add 1x on each side
-10=3x+2
subtract 2 on each side
-12=3x
devide by 3
-4=x
that's the x-information of the point. to get the y-information we plug it into one of the two function, any is fine actually, because the point we are looking for is on both of them after all.
