Question 81994
Actually they can.
{{{sqrt(20)/5-1/sqrt(5)}}}
to make this into one fraction, we have to find a common denominator, and we can do that by multiplying the top and the bottom of the second fraction by {{{sqrt(5)}}}:
{{{(sqrt(20)-sqrt(5))/5}}}
Now lets take a closer look at {{{sqrt(20)}}}
the number {{{20=4*5}}}
this means that {{{sqrt(20)=2*sqrt(5)}}}
So our equation above becomes:
{{{(2sqrt(5)-sqrt(5))/5=sqrt(5)/5=1/sqrt(5)}}}