The answer is 3. You would just match up the sides and combine the common things. 3z times z is 3z^2 because it would be the same number twice, not times two. Then 9 times 8 is 72. Z times 8 is 8z because it would be 8 times whatever number the variable was. Then lastly it’s 9 times 3 z. You’ll multiply the 9 times 3 to get 27. Then it would be 27z. 27z and 3z^2 cannot be added together because they are preforming different things. One is multiplying by the variable another is multiplying by 3 and the the variable to the 2nd power.