## mmbuckaroos 3 years ago cubed root of (-8x^9).... I have -2x^?

1. mmbuckaroos

|dw:1327286055825:dw|

2. mark_o.

(-8x^9)^1/3 =-2x^3

3. mmbuckaroos

so you just take the square root of the nine

4. mark_o.

take the cube root of -8 that is -2 and the x power of 9 divided by 1/3 power=3

5. mmbuckaroos

oh ok thank you

6. mark_o.

i mean multiplied by 1/3 or divided by 3

7. mark_o.

yw

8. mmbuckaroos

so what do you do if it says the cubed root of say 2? what is that then?

9. mark_o.

ok cube root of 2=2^(1/3) if you use a calculator =1.2599

10. mmbuckaroos

ok thanks I'm not really sure how to do this hw I have lol so Im just trying to piece it all together thank you!

11. mark_o.

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12. mark_o.

1.2599(1,2599)(1.2599)=1.2599^3 =2

13. mmbuckaroos

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14. mark_o.

a god example is cube root of -8 that is (-8)^1/3=-2 to check this (-2)x(-2)x(-2)=-8

15. mark_o.

(-2)(-2)(-2)= (-2)^3=-8 this is a cubed of -2,,, now its reversed is the cube root cube root of -8=(-8)^(1/3) =-2

16. mark_o.

if (-b)^1/3=-a then (-a)^3=-b

17. mmbuckaroos

right ok

18. mark_o.

algebraically,,,,if (-b)^1/3=-a here lets put both sides to the power of 3 [ (-b)^1/3 ]^3=[-a]^3 [ (-b)^3/3 ]=[-a]^3 [ (-b)^1 ]=[-a]^3

19. mark_o.

good luck now