How do you simplify the expression: 8u + 10u + -u - 7u

In the surface area formula for cylinders which expressionrepresents the lateral area

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

How many credit hours will a student have to take for the two tuition costs to be equal? round the answer to the nearest tenth of an hour.