How do you supposed to do this i need many method to do it.

I like the substitution method. Which is when you make one equation equal only x or y and plug it into the other equation)

There is also the graphing method. If you graphed it, it might not be quite as accurate (at least on hand, on computer you would be pretty exact)

Then there is the elimination method. You multiply one of the equations by a coefficient so that you can eliminate x or y from the equation. 

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!