# Manipulate formulas

Solve multi-variable formulas for a specific variable in order to solve some word problems.

### Problem

In physics, Albert Einstein's famous formula for mass-energy equivalence defines an object's energy, E, measured in joules left parenthesis, J, right parenthesis, in terms of its mass, m, measured in kilograms left parenthesis, k, g, right parenthesis, and the speed of light, c, measured in meters per second left parenthesis, m, slash, s, right parenthesis. The formula is commonly written as E, equals, m, c, start superscript, 2, end superscript.
Rearrange the formula to solve for mass left parenthesis, m, right parenthesis.
m, equals
Given that the speed of light is approximately 300, comma, 000, comma, 000, space, m, slash, s, what is the mass of an object that contains 1, point, 8, times, 10, start superscript, 14, end superscript, space, J of energy?