Question 87947
There are two ways to interpret what you are asking here.  One interpretation is this:  {{{sqrt(20/5) - 1/(sqrt(5)) }}}

The other interpretation is this: {{{(sqrt(20))/5 - 1/(sqrt(5)) }}} .  My guess is that you meant the second interpretation, since it matches with one of your multiple choice answers, so that is how I will solve it.


{{{(sqrt(20))/5 - 1/(sqrt(5)) }}}

Begin by simplifying the first square root and rationalize the denominator of the second fraction.  Do you understand how to do these steps?
{{{(sqrt(4)*sqrt(5))/5 - (1/(sqrt(5)))*((sqrt(5))/(sqrt(5)))}}}
{{{ (2*sqrt(5))/5 - 1*(sqrt(5))/5 }}}


It looks ugly, but at least you have a common denominator:
{{{(2*sqrt(5) - 1* sqrt(5))/5}}}


Combine like terms in the numerator:
{{{(1*sqrt(5)) /5}}}  or it can be written {{{(1/5)*sqrt(5)}}}, which is the D answer.


R^2 Retired from SCC