You should include parentheses in your question so we know exactly what's in the numerator and denominator and what's separate from the fractional part. (5-9)/2d is different than 5-(9/2d). I'm going to assume your problem is the second one.


First off, whenever you solve a problem like this, your goal should be to first collect all the terms with the variable on one side of the equals sign, and those without on the opposite side. Then, if the variable is in the denominator, you'll need to cross-multiply to get it out of the denominator. At that point, you just need to add/subtract/multiply/divide to get the variable by itself.

So in your specific example



the first step is to get the term with the "d" in it all by itself. So you can just subtract 5 from both sides:



There. Now the term with the "d" is alone on the left. Now you can multiply both sides by 2d to get rid of the fraction and get the "d" out of the denominator.

Can you take it from there?