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## Comment on

Operations with Roots## Sir in the related resources

## The Khan Academy questions

The Khan Academy questions provided on the linked page are not 700+ questions. If 700+ level questions do exist on the GMAT, they are likely VERY RARE.

So, you might want to see what you can find on GMAT Club.

## I need some help with this

## Here's my step-by-step

Here's my step-by-step solution: https://gmatclub.com/forum/root-9-root-80-root-9-root-95570.html#p1891953

## Thank you. Didn't see that

## Hi Brent,

In the video you pointed out that if a root is divided, the number in front of the root is divided and the number inside the root is. But how is (9√5)/(3√15) = 3/√3 when 9/3 is 3 and 5/15 is not 3?

Thanks for the reply!

## You're correct about the rule

You're correct about the rule.

In general we can say:

(w√x)/(y√z) = (w/y)(√(x/z))

So, 9/3 = 3

And √5/√15 = √(5/15) = √(1/3)

So, we get: (9√5)/(3√15) = 3√(1/3) which is the same as 3/√3

At this point, we can simplify 3/√3 by multiplying top and bottom by √3.

We get: (3√3)/3 which equals √3

Does that help?

Cheers.

Brent

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