## Key Concepts

**To Solve a Radical Equation:**- Isolate the radical on one side of the equation.
- Square both sides of the equation.
- Solve the new equation.
- Check the answer. Some solutions obtained may not work in the original equation.

**Solving Applications with Formulas****Read**the problem and make sure all the words and ideas are understood. When appropriate, draw a figure and label it with the given information.**Identify**what we are looking for.**Name**what we are looking for by choosing a variable to represent it.**Translate**into an equation by writing the appropriate formula or model for the situation. Substitute in the given information.**Solve the equation**using good algebra techniques.**Check**the answer in the problem and make sure it makes sense.**Answer**the question with a complete sentence.

**Area of a Square****Falling Objects**- On Earth, if an object is dropped from a height of \(h\) feet, the time in seconds it will take to reach the ground is found by using the formula \(t=\frac{\sqrt{h}}{4}\).

**Skid Marks and Speed of a Car**- If the length of the skid marks is
*d*feet, then the speed,*s*, of the car before the brakes were applied can be found by using the formula \(s=\sqrt{24d}\).

- If the length of the skid marks is

## Glossary

### radical equation

An equation in which the variable is in the radicand of a square root is called a radical equation