If we take the equation and multiply out the left side, we get....

+ 2xk +

=

+ x +

The x^2 and k^2 cancel out on both sides leaving us with this...
2kx = x
If we divide both sides by 2x to isolate k,
k ends up = 1/2
ZX is a diagonal line from corner to corner.
19) 5c+c=-6+2
6c=-4
c=-4/6
c=-2/3
20) -20-8=-2e
-28=-2e
28/2=e
14=e
21)p-2w=2l
(p-2w)/2=l
200+200+200+200+200+200+200+200+200
Answer:
568.3 into the nearest hundred
5.683