Before we look at adding, subtracting, multiplying and
dividing radicals, you should review radical simplifying.

Types of Radicals:


Adding and subtracting radical expressions is similar to operations with polynomials, except that individual radicals themselves can often be simplified after combining.

Adding Radical Expressions

Example 1:

   3√7 + 5√7 + 2√7

= 10√7     Just like combining x's


Example 2:

   (3√2 + 5) + (7√2 - 9)

= 3√2 + 5 + 7√2 - 9     with addition, the brackets are superfluous

= 10√2 - 4     Combine like terms


Example 3:

   4√5 + 2√11 + 4 + 8√5 + √11 - 1

= 12√5 + 3√11 + 3     Combine like terms


Example 4:

   5√12 + 2√27     No like terms, but the radicals will simplify

= 5√4√3 + 2√9√3

= 5(2)√3 + 2(3)√3

= 10√3 + 6√3     Now we have like terms to combine

= 16√3


Example 5:

   3√8  -  5√12  +  2  +  7√32  +  2√75  +  9     Simplify the radicals first

= 3√4√2  -  5√4√3  +  2  +  7√16√2  +  2√25√3  +  9

= 3(2)√2  -  5(2)√3  +  2  +  7(4)√2  +  2(5)√3  +  9

= 6√2 - 10√3 + 2 + 28√2 + 10√3 + 9    Combine the like terms

= 34√2 + 11     The √3 terms added to zero



Subtracting Radical Expressions

The only difference here is that any brackets in the expression will result in an additional step where we switch signs.

Example 6:

   (4√45 - 2√8 + 5) - (3√20 + 3√18 - 11)

=  4√45 - 2√8 + 5   - 3√20 - 3√18 + 11    Signs in the second bracket were switched

=  4√9√5  -  2√4√2  +  5  -  3√4√5  -  3√9√2  +  11     Simplify the radicals

=  4(3)√5  -  2(2)C2  +  5  -  3(2)√5  -  3(3)√2  +  11

=  12√5  -  4√2  +  5  -  6√5  -  9√2  +  11     Now combine likee terms

=  6√5 - 13√2 + 16


Example 7:

   (√6 - 4) - (3√6 + 5) + (8√6 - 1)

=  √6 - 4   - 3√6 - 5  +  8√6 - 1     Only the middle bracket had the signs switched

=   6√6 - 10


    Now let's look at multiplying radical expressions >>>


[ Adding & Subtracting | Multiplying | Dividing ]



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