Aprism is created using 2 regular pentagons as bases. the apothem of each pentagon is 2.8 centimeters.

which expression represents the volume of the prism, in cubic centimeters?

9x2 + 7x
14x2 + 7x
16x2 + 14x
28x2 + 14x

The volume of any solid shape takes a general equation of base times its height. The base referred to here is the area of one base of the prism. So, first, we determine the area of the pentagon. The equation is:

Area=1/2*apothem*perimeter -->perimeter is the sum of all side lengths
Area = 1/2*2.8*(5*x)   ---> perimeter is 5x because a regular pentagon has 5 equal sides
Area = 7x square units

Then, we use the formula for volume 
Volume=Area of base x height
Volume = 7x (2x+1)
Volume = 14x^2 + 7x cubic units

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.