Math: adding and subtracting radicals

Tutoring high school math, radicals are prominent.  The math tutor introduces addition and subtraction of them.

Adding radicals is much like adding variables. Note that x=1x; the 1 is understood to be there, but never written. Similarly, √3=1√3. Therefore, 2√5 + √5 = 3√5

You can’t simplify x plus y; x+y is just x+y. Similarly, √6+√7 doesn’t simplify. A calculator will give you a decimal for it, but that’s not an exact value.

So what about the following:

Example 1: Simplify √(12)+√(75)+√3

You may want to read up on simplifying radicals in my earlier post to understand what follows.

Solution: On the face of it, we can’t add the radicals because they’re not the same kind. However, we can simplify some of them as follows:

√(12) = 2√3

√(75) = 5√3

Simplifying reveals them to be the same kind. We indeed can add them.

√(12)+√(75)+√3 becomes

2√3 + 5√3 + √3 = 8√3

By a similar principle, √(50)-√8=5√2-2√2=3√2

I’ll be covering some different examples in an upcoming post:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

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