24. 1) =(4b +7a)/ab
2) =(9n -5) /mn
3) =(4*3 -2*11) /36xy =(12 -22) /36xy =(-10/36xy) =(-5/18xy)
4) = (10ab*5m +6b*2n -15a*7p) /(30a^2*b^2) =
=(50abm +12bn -105ap) /30a^2b^2
5) =(b(3a -4b) +8a^2 +4b^2)) /ab =
=(3ab -4b^2 +8a^2 +4b^2) /ab =
=(3ab +8a^2) /ab =a(2b +8a) /ab =(2b +8a)/b