Which of the following expressions are equivalent to −3.5(2 − 3n) − 2.5n?

a. −7 − 8n
b. −7 + 8n
c. −7 − 13n
d. −7 − n(10.5 − 2.5)

At a sand and gravel plant, sand is falling off a conveyor and onto a conical pile at a rate of 16 cubic feet per minute. the diameter of the base of the cone is approximately three times the altitude. at what rate is the height of the pile changing when the pile is 12 feet high? (hint: the formula for the volume of a cone is v = 1 3 πr2h.)

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way

Acomputer store buys a computer system at a cost of $370.80. the selling price was first at $ 618, but then the store advertised a 20 % markdown on the system. answer parts a and b. a. find the current sale price.