How do I rewrite algebraic fractions as a single fraction?

The first step to writing an expression with more than one fraction as a single fraction is to find their lowest common denominator. For example, in a question with two fractions where the denominators are x+3 and x+4, the lowest common denominator would be (x+3)(x+4). The numerators of the two individual fractions are then multipled by the same number that the denomiators needed to be multiplied by to achieve the lowest common denominator. For the example above, the fraction with x+3 as its denominator would be multiplied above and below by (x+4). The fraction with x+4 as its denominator would be multiplies above and below by (x+3). The two fractions are then combined as one with the lowest common denominator on the bottom and all the terms on the numerator of both fractions on top. Any simplification that needs to be carried out can then be done.