The first step is to factor the denominators so you can find the LCD:
Next, you must compare each denominator to the LCD, and decide what factors are missing from each of the denominators. Notice the in the first denominator, you are missing a factor of (y+1), and in the second denominator, you are missing a factor of (y-7). So multiply the first fraction by and multiply the second fraction by the missing factor which is . It should look like this:
Now that you have a common denominator for the fractions, you can multiply out the numerators and place the result over the common denominator.
Combine like terms in the numerator, and see if the numerator can be factored. In this case, it cannot, so what you have is the final answer:
