Simplify this expression. 3x2(7x2 − 9)
a) 21x2 − 9
b) 21x2 − 27x2
c) 21x4 − 9
d) 21x4 − 27x2

Frank has a devised a formula for his catering business that calculates the number of meatballs he needs to prepare. the formula is m=4a+2c, where c=number of children; m=number of meatballs; a=number of adults. how many meatballs are required for a party of 10 adults and 5 children?

Abox holds 500 paperclips. after a week on the teacher's desk 239 paperclips remained. how many paperclips were used?

Aramp rises 4 feet over a distance of 10 feet. what is the length of the ramp?