When you are given a "solution" as a paired value, it means you can substitute these values in for your x and y variables and the equation will work. I'll show you how to do this with a slightly different set of numbers and you can try it on your own numbers.
If a solution of the equation 3x = 26 - cy is (6,4) then what is the value of c?
Solution: First substitute the value 6 for every x you see and substitute 4 for each y:3x = 26 - cy
3(6) = 26 - c(4)
18 = 26 - 4c
Now solve for c by re-arranging the equation:4c = 26 - 18
4c = 8
c = 2
Hope this example helps you!