if a = 1, find the values of b, c, and d that make the given expression equivalent to the expression below.

To do this, you need to multiply out the expressions. This is a bit tedious, but remember like FOIL for binomials, for these trinomials you must multiply each term. If you need a step-by-step, I'd be happy to provide it. Let me know.

Once you have simplified the expression, you get
.

But, the problem stipulates that a must equal 1. We can equivalently factor out the negative sign and put it on the denominator with no change to write 
.

So, seeing where each coefficient corresponds between the two expressions, you get a = 1, b = 9, c = –2, and d = 4.

Could you make it more clear?