i am having trouble on solving fractional equations such as:

2 3 7
______ + _____ = ______________
x+3 x+4 x^2 +7x+12

factor the right side denominator, then look for what factors make up a common denominator. For each fraction, multiply the numerator and denominator with the factors of the lcd not present. Look at this example:

http://www.themathpage.com/alg/add-algebraic-fractions.htm