Which expression has a value of –12?
a. –4 – (–8)
b. 3 – 9
c. –16 – (–4)
d. –6 – 18

(98 points) i need with 5 questions. answer definitions are welcomed, but not necessary.

Neveah and clint are baking muffins for the bake sale. they need to bake 30 muffins for their display case. clint has baked 4 so far, and neveah has baked 7. how many muffins (m) do they have left to bake? show your work!

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.