The eqaution d=m/v can be used to calculate the density d an object with a mass and volume v. which is an equivalent equation solved for v

v =

given d =

multiply both sides of the equation by v, hence

dv = m ( divide both sides by d )

v =

D

Step-by-step explanation:

You have to be careful that you treat 21 as special. It is the only positive number. As you do the problem, keep an eye on 21.

f(-2) = 3x^2 - 2x + 5                Put -2 wherever you see an x

f(-2) = 3(-2)^2 - 2(-2) + 5         Calculate the first term.    

f(-2) = 3(4) - 2(-2) + 5              Remove the brackets of the second term

f(-2) = 12 + 4 + 5                     Combine

f(-2) = 21