Question 75187
Anything to the half power is the same as taking the square root. For instance {{{sqrt(x)=x^(1/2)}}} so 
{{{y= -2(x-3)^(1/2)}}} can be written as {{{y= -2*sqrt(x-3)}}}
As a general rule this is true:

{{{x^(1/n)=root(n,x)}}}