By equations, we can put this.
Rent: 50x + 800
Take-home Pay: 15x + 1500
So we need them to be together, which means we combine the two equations.
50x + 800 = 15x + 1500
minus 800 by both sides
50x = 15x + 700
minus 15x by both sides
35x = 700
divide 35 by both sides
x = 20
Double check:
50(20) + 800 = 15(20) + 1500
1000+800 = 300 + 1500
1800 = 1800 √