Algebra II Help -- I Don't Understand My Teacher.

rrhett

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Mar 30, 2012
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Okay, in Algebra II class, we've been learning about radicals. I'm generally pretty good at simplifying them, but there's one type of problem in particular that I guess just didn't register in my brain correctly. It looks something like this:

4√5
------
4
√15

(The dotted line is suppose to represent the fraction line.)

These are the first couple of steps that I think I remember learning.

4√5 √15 4√75
------
• ------ = -------
4
√15 √15 4

And I'm not completely positive that is right, but it seems to be what I remember. And after that, the 4's cancel out and you just take the square root of 75 like normal. Honestly, though, I feel as though it's wrong. I have a test on this stuff tomorrow and I really need to know how to do it! Thanks for your time.

 
\(\displaystyle 4/frac{/sqrt5}{4 /sqrt15}\)

\(\displaystyle 4/frac{/sqrt5}{4/sqrt3 /sqrt5}\)

* The numerator/denominator 4's and square root of 5's cancel leaving you with:

\(\displaystyle /frac{1}{/sqrt3}\)
 
Last edited:
Hello, rrhett!

. . . . . . . . 4√5
Simplify: .--------
. . . . . . . 4√15

. . . . . . . . . . . . . . . . √5
First, cancel the 4's: . ----
. . . . . . . . . . . . . . . .√15


. . . . . . . √5 . . . . . . .√5 . . . . . .1
Then: . -------- . = . ------- . = . ----
. . . . . .√(3)(5) . . . .√3√5 . . . . √3


. . . . . . . . . . 1 . . √3 . . . . .√3
Rationalize: .---- . ---- . = . ----
. . . . . . . . . .√3 . .√3 . . . . . 3
 
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