SOLUTION: Trying to help my son who is a military student in Hawaii!! find the variable for each parallelogram RZ=2x+5 SW=5x-20 Rectangle has a line through one diagonal of RZT and

I will assume thie rectangle is like this:



The red line RZ is 2x+5.  

The diagonals of a parallelogram bisect each other.

The red line RZ, which is 2x+5 is one-half of the diagonal RT.

The diagonals of a rectangle are equal.  So

    2(RZ) = RT = SW

    2(RZ) = SW

2(2x + 5) = 5x - 20
 
  4x + 10 = 5x - 20

       30 = x

Edwin