Literal Equations
A literal equation is also called a formula. It expresses a relationship among several quantities, each of which can take on different values. this means that the equation will have several different variables in it. An example is the formula for the area of a triangle:
In this formula A is the area of the triangle, b is the length of the base, and h is the perpendicular height of the triangle.
This formula allows us to calculate the area of a triangle if we know its base and height. Now suppose that we already know the area and the base, but we want a formula that will give the height. We can use our algebraic methods to isolate the variable h in the formula:


Clear Fractions (multiply both sides by the denominator 2) 

Divide by b to isolate h 
We say that this new formula gives h in terms of A and b. Given values for A and b, we could plug them into this formula to calculate the value of h.
To solve a literal equation for a particular variable, isolate that variable on one side of the equation using the addition and multiplication principles, treating all the other variables as though they were constants. 