Simplify a - {5b - [a - (3b - 2c) + c - (a - 2b - c)]}.

-a - 6b + 4c
a - 6b + 4c
a - 10b + 4c
-a + 10b + 4c

You decide instead to take the train there. the train will take 135 minutes. convert this into hours and minutes.

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

The diameter of the moon is about 3500 km. approximate the surface area of the moon using the formula for the surface area of a sphere, s = 4πr2. write your answer in scientific notation.