sum of -x 7/2x 4 and2x 5/2x 4 I will take a guess that + signs are missing (because that often happens) and also - signs are OK. But there's still something missing, such as an exponent on the first term. And the 7/2x and 5/2x could be read either as (7/2)x and (5/2)x or they could be 7/(2x) and 5 ...