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View Full Version : Algebra 2, multiplying "roots", square, cube, etc.


Renaejrk
Apr 15, 2007, 09:03 PM
My friend's son knows I'm good at math and was having some algebra 2 problems. He showed me his problem and I couldn't remember how to do it! He left his book at school and the homework is due in the morning. I told him I'd look into it and see if I could help! I don't know how to even type his problem, but can explain it, I think!

cube root of 25 x cube root of 25

There are a couple of other problems that are not cube, but have like a 6, or other numbers to show what root it is, I'm assuming? Don't remember this from College Algebra!:confused:

whiteladybug2002
Apr 15, 2007, 09:17 PM
Ok, I will try to help? Luckily I have an old algebra book here to help me.

multiply the numbers under the root sign and them take the cubed root of the answer

ex. Cube root of 25 x cube root of 25 = cube root of 625 = 8.5498

You will do the same with all the other numbers too!

Hope I helped and didn't confuse worse!

Good Luck and God Loves You!

Renaejrk
Apr 15, 2007, 09:23 PM
Ok, I will try to help?! Luckily I have an old algebra book here to help me.

multiply the numbers under the root sign and them take the cubed root of the answer

ex. cube root of 25 x cube root of 25 = cube root of 625 = 8.5498



What about if the "root" numbers are different? Such as 6th root of 25 x 4th root of 10? (just coming up with #s off the top of my head!)

whiteladybug2002
Apr 15, 2007, 09:37 PM
That is a good question, but I hope I have the answer. It is quite a bit hard to explain, but I will give you the example in my book.

ex.
Step 1. 6 X the 5th root of 4x + 3 X the 5th root of 4x - cube root of 4x

Step 2. (6+3) X 5th root of 4x - cube root of 4x

Step 3. 9 X 5th root of 4x - cube root of 4x (Because the indices differ, it we are done)

I know there is a nice program out there that will make all this nice and pretty, but I don't have it so I work with what I got. Sorry if this is confusing.

Renaejrk
Apr 15, 2007, 09:47 PM
ex.
Step 1. 6 X the 5th root of 4x + 3 X the 5th root of 4x - cube root of 4x

Step 2. (6+3) X 5th root of 4x - cube root of 4x

Step 3. 9 X 5th root of 4x - cube root of 4x (Because the indices differ, it we are done)

.
You are being a big help!

Question - if it were all x the cube root of 4x instead of subtracting, what would you do?
ex - 9(5th root of 4x) (cube root of 4x)?

whiteladybug2002
Apr 15, 2007, 10:00 PM
I am thinking and looking through this book. It may take a minute, if I remember?

Renaejrk
Apr 15, 2007, 10:18 PM
Don't stay up trying to figure it out! I have to go to bed, he may just have to talk to one of his friends before class and maybe they'll have enough time to help him - I hate not knowing something - it's the first time he's asked me and I didn't know! LOL!