How to find the intersection point of the lines y=1008-2x and y= -x ?

The main property of an intercepting point is:
it's coordinates verify the equations of the curves that are
intercepting.

If M(x,y) is the intersection point for the
given lines, that means that the values for it's coordinates are the solution of the
system formed by the equations of the lines.

So, in order
to find out the values of the coordinates of the intercepting point, we have to solve
the system:

Since the 2nd equation is y  =-x, we'll
substitute it into the first equation:

-x = 1008 -
2x

We'll move all terms in x to the left side and we'll
keep the numbers to the right side:

2x - x =
1008

x = 1008

But x =
-y

y=-1008

The 
values of the coordinates of the intercepting point are :
M(1008,-1008).