I think so,to subtract or add the rational expression first find the LCD of denominators if they unlike terms ex.
3/4+2/5=the LCD of 4 and 5is 20 second is 20 divide 4(the denominator)=5x3=15,first 20 divide 5=4x2(in numerator)=8 now u add the numerator to numerator
15/20+8/20=23/20 the answer.
