How do you simplify 8^(2/3)823?

2 Answers
Jul 24, 2016

=4=4

Explanation:

8^(2/3)823 can be written as
root3(8^2382
=root3(64)=364
=root3((4)(4)(4)=3(4)(4)(4)
=4=4

Jun 30, 2017

44

Explanation:

One of the laws of indices states: x^(m/n) = rootn((x^m)) = (rootn(x))^mxmn=n(xm)=(nx)m

Therefore 8^(2/3)823 can be written as root3((8^2)) or (root3(8))^23(82)or(38)2

I prefer to use the second form because it uses smaller numbers - the root is found first and then that is squared.

root3(8) = 2 and 2^2 =438=2and22=4

So: (color(blue)(root3(8)))^2 = color(blue)(2)^2 = 4(38)2=22=4

Consider a question such as 32^(3/5)3235

root5(color(blue)((32^3)))5(323) would mean finding 32^3323 first ... ouch!

(color(blue)(root5 (32)))^3(532)3 would mean finding root5(32)532 first. That is color(blue)(2)2

(color(blue)(root5 (32)))^3 = color(blue)(2)^3 = 8(532)3=23=8