You do what you would normally do if there were no variables in the expression. You already learned this. Find lowest common denominator, change each fraction to equivalent form having the common denominator, perform the addition with the numerators, and then simplify, bring to lowest terms.
Factor those factorable denominators first.
and
The necessary lowest common denominator is .
APPLY the Common Denominator:
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Not much more can be done. Best form of answer would be either
OR