Combining Radical Expressions
Reference > Mathematics > Algebra > Simplifying RadicalsIn the first section, we talked about the importance of simplifying radical expressions, and there's a reason for doing this that we didn't mention then: writing radical expressions in simplest form may allow us to combine terms and simplify an expression even more.
Take the following expression as an example:8
+ 18
+ 50
This expression can be simplified by first simplifying each individual term:
8
+ 18
+ 50
=4
2
+ 9
2
+ 25
2
= 2
2
+ 32
+ 52
Now, we notice that in each case we have a number multiplied by 2
, so they are essentially like terms or "like radicals," and we can combine them in the same way that we combine like terms.
22
+ 32
+ 52
= (2 + 3 + 5)2
= 102
.
Of course, we won't always have like radicals when we simplify, but when we do, we can combine them. Here's an example: Simplify the expression 2
+ 3
+ 12
+ 98
.
2
+ 3
+ 12
+ 98
= 2
+ 3
+ 4
3
+ 49
2
=2
+ 3
+ 23
+ 72
Note that we have two terms with 2
and two terms with 3
. These pairs of terms can be combined:
2
+ 3
+ 23
+ 72
= (1 + 7)
2
+ (1 + 2)3
= 8
2
+ 33
The same process will work with variables, and it will also work with cube roots and other radicals. Simplify the following expression: 3
8x43
27x4When we simplify each of these, we obtain:
2x3
x3
x3
xQuestions
1.
Simplify
10
+ 40
2.
Simplify
x
+ 9x
3.
Simplify
5
+ 20
+ 18
+ 50
4.
Simplify +
3
163
1285.
Simplify -
4
81x54
x5Assign this reference page
Click here to assign this reference page to your students.Cube Roots and Other Radicals
Rationalizing the Denominator - Part One
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