Key Concepts

- Denominators may be eliminated from rational equations by multiplying each term in the equation by the lowest common denominator (LCD).
- Declare values of the variable that could cause any denominator to equal zero before reducing or solving, then exclude those values from the solution set for the equation.
- The formula for the perimeter of a rectangle of length L and width W is [latex]P=2L + 2W[/latex]
- The formula for the area of a rectangular region of legth L and width W is [latex]A=LW[/latex]
- The formula for the volume of a rectangular solid of length L, width W, and height H is [latex]V = LWH[/latex]
- The formula that relates distance, rate, and time is [latex]d = rt[/latex]
- A formula may be rearranged by algebraically isolating any one of the variables as desired
- Inequalities may be expressed in words, by using an inequality symbol, or graphed on a number line.

## Glossary

**area**- the size of the surface of a two-dimensional figure
**inequality**- a mathematical statement that compares the size or value of two mathematical expressions
**LCD**- lowest common denominator, the smallest possible expression into which each denominator will factor evenly.
**perimeter**- a measure of the linear distance around the edges of a two-dimensional figure
**rational equation**- any equation containing a variable expression in one or more denominators
**volume**- the size of the space contained within the edges of a three-dimensional figure