1) (5x/(ab)) +(2y/(3a^2b))-3/(6a^2b^2)= =(5x/(ab)) +(2y/(3a^2b))-1/(2a^2b^2)= =(30xab /(6a^2b^2)) + (4yb/(6a^2b^2))-3/(6a^2b^2))= =(30abx+4yb-3)/(6a^2b^2)