Simplifying Radicals
The student is able to (I can):
• Simplify a square root
• Multiply square roots
Square Roots
• When we are taking the square root of a number, we will
not always get a whole number answer.
• If your answer is not a whole number, then the number
your calculator gives you is a decimal approximationapproximationapproximationapproximation. This
is an irrational number, like π, which goes on forever.
• If I ask for an exact answerexact answerexact answerexact answer, I do notnotnotnot want a decimal – I
want you to leave it as a simplified radicalsimplified radicalsimplified radicalsimplified radical.
To simplify a radical (square root):
• Find all the prime factors of the number
• Group pairs of factors – these can be pulled out of the
radical
• Any factors that cannot be paired up must stay inside the
radical
Example: Simplify 24
24
2 12
To simplify a radical (square root):
• Find all the prime factors of the number
• Group pairs of factors – these can be pulled out of the
radical
• Any factors that cannot be paired up must stay inside the
radical
Example: Simplify 24
24
2 12
2 6
2 3
To simplify a radical (square root):
• Find all the prime factors of the number
• Group pairs of factors – these can be pulled out of the
radical
• Any factors that cannot be paired up must stay inside the
radical
Example: Simplify 24
24
2 12
2 6
2 3
To simplify a radical (square root):
• Find all the prime factors of the number
• Group pairs of factors – these can be pulled out of the
radical
• Any factors that cannot be paired up must stay inside the
radical
Example: Simplify 24
24
2 12
2 6
2222 3333
=i2 2 3 2 6
Examples
Find the value of x. Reduce radicals to simplest form.
1.
2.
2
6
x
15 10
x
Examples
Find the value of x. Reduce radicals to simplest form.
1.
2.
2 2 2
2 6 x+ =
2
4 36 x+ =
2
40 x=
2 10x =
2
6
x
15 10
x
Examples
Find the value of x. Reduce radicals to simplest form.
1.
2.
2 2 2
2 6 x+ =
2
4 36 x+ =
2
40 x=
2 10x =
2 2 2
10 15x + =
2
100 225x + =
2
6
x
15 10
x
2
125x =
125x =
5 5=
When you multiply radicals, you multiply the numbers on the
outside, then multiply the numbers on the inside, and
simplify if necessary.
Example: Multiply ( )( )3 3 2 6
( )( )
( )( )
3 2 6
3 6 18 3 2
=
= =
( )( ) ( )( ) 23 3 2 6 6 3 82 1= =
Sometimes in problems, you will be asked to square a square
root.
Example: Evaluate
• Square the outside term:
• Squaring a square root removes the square root, so
• Multiply.
( )
2
5 3
2
5 25=
( )
2
3 3=
( )( )25 3 75=

2.3 Simplifying Radicals

  • 1.
    Simplifying Radicals The studentis able to (I can): • Simplify a square root • Multiply square roots
  • 2.
    Square Roots • Whenwe are taking the square root of a number, we will not always get a whole number answer. • If your answer is not a whole number, then the number your calculator gives you is a decimal approximationapproximationapproximationapproximation. This is an irrational number, like π, which goes on forever. • If I ask for an exact answerexact answerexact answerexact answer, I do notnotnotnot want a decimal – I want you to leave it as a simplified radicalsimplified radicalsimplified radicalsimplified radical.
  • 3.
    To simplify aradical (square root): • Find all the prime factors of the number • Group pairs of factors – these can be pulled out of the radical • Any factors that cannot be paired up must stay inside the radical Example: Simplify 24 24 2 12
  • 4.
    To simplify aradical (square root): • Find all the prime factors of the number • Group pairs of factors – these can be pulled out of the radical • Any factors that cannot be paired up must stay inside the radical Example: Simplify 24 24 2 12 2 6 2 3
  • 5.
    To simplify aradical (square root): • Find all the prime factors of the number • Group pairs of factors – these can be pulled out of the radical • Any factors that cannot be paired up must stay inside the radical Example: Simplify 24 24 2 12 2 6 2 3
  • 6.
    To simplify aradical (square root): • Find all the prime factors of the number • Group pairs of factors – these can be pulled out of the radical • Any factors that cannot be paired up must stay inside the radical Example: Simplify 24 24 2 12 2 6 2222 3333 =i2 2 3 2 6
  • 7.
    Examples Find the valueof x. Reduce radicals to simplest form. 1. 2. 2 6 x 15 10 x
  • 8.
    Examples Find the valueof x. Reduce radicals to simplest form. 1. 2. 2 2 2 2 6 x+ = 2 4 36 x+ = 2 40 x= 2 10x = 2 6 x 15 10 x
  • 9.
    Examples Find the valueof x. Reduce radicals to simplest form. 1. 2. 2 2 2 2 6 x+ = 2 4 36 x+ = 2 40 x= 2 10x = 2 2 2 10 15x + = 2 100 225x + = 2 6 x 15 10 x 2 125x = 125x = 5 5=
  • 10.
    When you multiplyradicals, you multiply the numbers on the outside, then multiply the numbers on the inside, and simplify if necessary. Example: Multiply ( )( )3 3 2 6 ( )( ) ( )( ) 3 2 6 3 6 18 3 2 = = = ( )( ) ( )( ) 23 3 2 6 6 3 82 1= =
  • 11.
    Sometimes in problems,you will be asked to square a square root. Example: Evaluate • Square the outside term: • Squaring a square root removes the square root, so • Multiply. ( ) 2 5 3 2 5 25= ( ) 2 3 3= ( )( )25 3 75=