Question 11850
If I am reading you right, you mean this: 
{{{(1/3)*(((2a)/5)-3)+4/15-2/3}}}


By distributive property:
{{{(2a)/15-3/3 + 4/15 - 2/3 }}}


It may help to find a common denominator of 15:
{{{(2a)/15 - 15/15 + 4/15 - 10/15}}}
{{{ (2a-15 + 4 - 10)/15}}}
{{{ (2a - 21)/15}}}


R^2 at SCC