RADICAL EXPRESSIONS An expression written with a radical symbol is called
a radical expression, or sometimes just a radical.
4
EXAMPLE
Evaluate a Radical Expression
Evaluate b2
4ac when a 1, b 2, and c 3.
Solution
The radical symbol is a grouping symbol. You must evaluate the expression
inside the radical symbol before you find the square root.
b2
4ac (
2
)2
4(1
)(
3)
Substitute values for a, b, and c.
4
2
1
Simplify.
16
Add.
4
Find the positive square root.
Evaluate a Radical Expression
Evaluate
b
2
4ac for the given values.
13. a 2, b 3, c 5
Student Help
KEYSTROKE HELP
To find the square root
of 3 on your calculator
you may need to press
or
. Test your
calculator to find out
which order it uses.
5
EXAMPLE
14. a 1, b 8, c 20
Use a Calculator to Evaluate an Expression
1 23
Use a calculator to evaluate . Round the results to the
4
nearest hundredth.
Solution
When the symbol precedes the radical, the expression represents
two different numbers.
KEYSTROKES
DISPLAY
1
2
3
4
1.116025404
1
2
3
4
0.616025403
ANSWER 䊳
The expression represents 1.12 and 0.62.
Use a Calculator to Evaluate an Expression
Use a calculator to evaluate the expression. Round the results to the
nearest hundredth.
2 3
2 36
16. 4 8
17. 18. 15. 6 5
3
4
9.1
Square Roots
501