Notice that the fractions have different denominators, hence, you need to arrive to a common denominator multiplying the different denominators such that:
Notice that the third fraction has equal denominator to the one of the first fraction, hence, you need to consider one time.
Hence, evaluating the algebraic expression yields
It is not so complicated, at all!
First, you'll have to check if the fractions have the same denominator.
If the answer is yes, you'll just have to add or subtract the terms from numerator.
If the answer is no, the next step is to calculate the least common denominator.
In this case is:
LCD = 2*3*5*(x-3)(x+3)
We'll write the product (x-3)(x+3) = x^2 - 9 (diff. of squares)
We'll multiply each ratio by LCD.
36(x-3) + 36(x+3) - 17(x+3)
We'll remove the brackets:
36x - 108 + 36x + 108 - 17x - 51
We'll combine and eliminate like terms and we'll get:
55x - 51