Question 193581
Note that:
{{{a^(-1)=1/a}}}
And
{{{a^0=1}}}
So
{{{5^(-1)+2^(-1)-3^0}}}
={{{1/5+1/2-1}}}
={{{2/10+5/10-10/10}}}
={{{(2+5-10)/10}}}
={{{-3/10}}}