Section 6.4 Addition & Subtraction of Radicals
HOMEWORK: Sec 6.4: 1 - 79 odd
Definition: Two radical expressions are like radicals if they have the
same index and same radicand.
Example: Determine if the following are like radicals:
2 x
4
and
1
2 x and
3
4

2x
4
2x
5
1
1
2 x and
2x
3
3
3
Strategy: To add or subtract like radicals, we use the
distributive property. Note, you may need to simplify the
radicals first!
Example: 3 5  4 5  5
Watch for common mistakes!
Note: 3 5  4 5  5  6 15
x y  x  y!
Page 1
Section 6.4 Addition & Subtraction of Radicals
Example: Add or subtract and simplify
1
2 x 3xy  x 3xy
4
3
2x
3
2
2
3
1
1
24 xy  y 3x y 
81x y
2
4
5
3
4
2
3
4
5
Page 2
Section 6.4 Addition & Subtraction of Radicals
Additional Examples From text:
#12
#24
#26
#30
#34
Page 3
Section 6.4 Addition & Subtraction of Radicals
#40
#54
#58
#60
Page 4
Section 6.4 Addition & Subtraction of Radicals
#64
#66
#68
Page 5