Question 104973
{{{(6-a/b)/(12/b)}}}
{{{(b(6-a/b))/(b(12/b))}}} Multiply numerator and denominator by b. 
{{{((6b-a(cross(b))/cross(b)))/(12cross(b)/cross(b))}}} Distribute. 
{{{(6b-a)/12}}}Simplify. 
{{{6b/12-a/12}}}Distribute. 
{{{b/2-a/12}}}Final answer.