Solve a formula for a specified variable
In some applications, the appropriate formula may be solved for a different variable than the one to be found. For example, the formula I = prt says that interest on a loan or investment equals principal (amount borrowed or invested) times rate (percent) times time at interest (in years). To determine how long it will take for an investment at a stated interest rate to earn a predetermined amount of interest, it would help to first solve the formula for t. This process
is called solving for a specified variable or solving a literal equation.
Solving for a Specified Variable
Step 1 Transform so that all terms containing the specified variable are on one side of the equation and all terms without that variable are on the other side.
Step 2 If necessary, use the distributive property to combine the terms with the specified variable.* The result should be the product of a sum or difference and the variable.
Step 3 Divide each side by the factor that is the coefficient of the specified variable.