Help me please?

The surface area (sa) of a cube with a as the length of each of its sides is given by the formula . if the surface area is known, how can you rewrite the formula to find its side?

One cell phone plan charges $20 per month plus $0.15 per minute used. a second cell phone plan charges $35 per month plus $0.10 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.

Which diagram best shows how fraction bars can be used to evaluate 1/2 divided by 1/4?