## yrivers36 3 years ago Just want to check to make sure answer is correct. Simplify the expression. sqrt of x divided by cubed rt of (27x^6). The answer that I got was 1/3x. Please explain.

1. campbell_st

$x^{1/2}/(27x^6)^{1/3} = x^{1/2}/3x^{2} = 1/3 x^{1/2 - 2}$ I got $1/3x^{-3/2} = 1/(3\sqrt{x^3})$

2. yrivers36

Im will draw the equation

3. yrivers36

|dw:1333140979846:dw|

4. campbell_st

yep my answer still holds... in the denominator (27x^6)^1/3 = 3x^2 so x^(1/2)/3x^2 = 1/3 x(1/2 - 2) = 1/3 ( x(-3/2))

5. yrivers36

yes

6. Directrix

|dw:1333141131164:dw|

7. yrivers36

so then it is 1/3x?

8. Directrix

No. Square root of x and then just x are not the same so they do not divide out. Think of square root of 4 and then just 4. They do not divide to 1.

9. campbell_st

index rule for division... subtract the powers x^{1/2} / 3 x^2 = 1/3 x^1/2 - 2} = 1/3 x^(-3/2)

10. yrivers36

what I think I was doing was taking the sqrt of x which I think = x and then canceling out one the x on the numerator and one x from denomenator

11. Directrix

That is the error pattern I saw. I say "error pattern" because it is a common error in Algebra.

12. yrivers36

oh so just leave it as the sqrt of x

13. AsianDuck

|dw:1333141629395:dw| as campbell stated

14. Directrix

What are the instructions for the problem? If you were doing rational exponents, then I would not leave it as sqrt of x. By rational exponents, I mean something like x^(1/2).

15. yrivers36

it says Use properties to simplify the expression. Answer should NOT include any negative exponents.

16. AsianDuck

17. Directrix

@yrivers36 --> The instructions "sound" as if you were to do rational exponents but I am guessing. Usually the instructions are more explicit.

18. yrivers36

thats all that is there

19. Directrix

20. Directrix

What sort of properties are in the book to which the instructions "Use *properties* to simplify the expression." Were any of the properties for rational exponents. If so, you'll see a property such as the following: x^a / x^b = x^ (a - b).

21. yrivers36

checking now

22. yrivers36

it says follow the quotient rule for radical expressions. I found this in the book but the problem is on the lab

23. Directrix

I think I would leave the answer as sqrt of x over the quantity (3x^2) but consider showing on the side of the paper the continuation to rational exponents. Just a second, and I'll check the quotient rule for radical expressions. Also, I'll upload some properties of rational exponents for you to view.

24. yrivers36

Thank you so much

25. Directrix

I have decided that based on this, if I were doing the problem for class, I would leave the radical in the answer and stop there.

26. yrivers36

ok i will do it that way

27. Directrix

Okay, and here's the link for the Quotient Rule. The section I uploaded was truncated. In case you want to practice on other problems, you can go to the source: http://www.mathportal.org/algebra/roots-and-radicals/simplifying-radical-expressions.php