To get the simplest radical root form for a non-perfect square, always factor out the number first.
So, for 18, find the factors.
18
6 3
2 3 3
2 3²

so, when you find a pair of the same two numbers, they become squared. Eliminate the squared signs; that number goes to the left, and the left over numbers are multiplied and are put into the square root sign. So, you end up with the final answer:

3 $\sqrt{2}$

3 0

4 years ago

(4/9)-¹ ?????????? what is it? <br> -9/4<br> -4/9<br> 9/4

Elis [28]

Im not sure on the syntax here, but i assume the question is (4/9)^-1

(4/9)^-1
= (4^-1)/(9^-1)

A negative power is an inverse of the positive power
i.e. x^-2 = 1/x^2
This is because if we have say x^3/x^5 we simplify it by cancelling x^3 which gives 1/x^2.
Another way to think of it is to subtract the power of the bottom x from the power of the top x: 3-5 = -2 so x^3/x^5 = x^-2.
I hope this explains how negitive powers are the inverse of the positive power.

So....
(4^-1)/(9^-1)
= 9/4
Because the inverse of 4 is 1/4 and the inverse of 1/9 is 9

8 0

4 years ago