The area of a rectangular classroom is given by the trinomial a - 4a - 21. the length of the rectangle is a+3. what is the expression for the width of the classroom?

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.

Aschool allots ? 1500 to spend on a trip to the theatre. theatre tickets have a regular cost of ? 55 each and are on offer for 1 5 off. a train ticket for the day will cost ? 12 each. if 2 teachers and the maximum number of students attend, how much money will the school have left over?

Solve the equation for x. 50(4x + 12) = 200