Assuming that P1 and P2 are the same for #1-#4, we can simplify and solve this system of equations:

For simplification, I've replaced P1 = a & P2 = b.

First: #1 = #2

we can divide by 2 to get:

which we will denote equation (1)

Second: #3 = #4

which we will denote equation (2)

Then we attempt to solve this linear system of equations by adding the two equations:

(1)

(2)

Then we can substitute this answer back into equation (1):

(1)