Question

need help

Answer 1

The bottom of a fraction is called the denominator.
Numbers like 2 and 3 are rational.
But many roots, such as √2 and √3, are irrational.
So you need to have a rational numeber instad of the root

Multiply top and bottom by the square root of 8x,

on the denom: √8x × √8x = 8x:
On num: √8x × 1 = √8x

Answer 2

multiply both top and bottom by the conjugate of the denominator.

here you can find all the details: https://www.mathsisfun.com/algebra/rationalize-denominator.html