Literal Equation - An equation that contains two or more variables (or letters).  For example:

4x + 2y = 16

A = ¹/₂bh

C = d

... are all literal equations.  

N.B. One meaning of the word "literal" is defined as being "expressed by letters"... so a literal equation is simply an equation expressed using letters... literally!!

Real-life applications of literal equations are often called FORMULAS.  For example, we know that distance traveled (d) is equal to the rate of speed (r) multiplied by the amount of time (t) spent traveling.  So the literal equation:

d = rt
distance = (rate)(time)

gives us a formula for solving for distance traveled, IN TERMS OF a given rate of speed and given time.

Use your equation solving skills to create various formulas from literal equations by solving for ANY of the literals (variables).

DO NOW:

1) WHAT IF you know the distance traveled and the rate of speed?  Can you develop a formula to express time (t) in terms of distance (d) and rate (r)? Hint: SOLVE for t (our target is "t = ")

1b) Use your formula to determine the amount of time required to travel 800 miles at a speed of 50 miles per hour.

2) Volume of a cylinder: 

Can you develop a formula to express the height (h) in terms of volume (V) and radius (r)?

2b) Use your formula to determine the height of a cylinder that has a volume of 25 cubic inches and a radius of 2 inches (use 3.14 for pi).

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