Question 171344
(7a^2b + 4ab) + (9a^2b - 8ab) - (11a^2b + 14ab)

Change the sign for the terms folling the negative sign

- (11a^2b + 14ab)=- (11a^2b + 14ab =-11a^2b -14ab

Then combine like terms and simplify


7a^2b + 4ab+ 9a^2b - 8ab-11a^2b -14ab
(7-11+9)a^2b +(4-8-14)ab=5a^2b-18ab