Root 16 multiplied by root 16

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

Which sentence uses an objective tone? we will plant the best garden of any school in the area. the new campus garden will surely be envied by other schools. a garden would provide numerous benefits to the students. you will probably agree that gardens have many benefits.

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?