Question 30597
Solve for n:
{{{A = (1/2)h(m+n)}}} Multiply both sides by 2.
{{{2A = h(m+n)}}} Divide both sides by h.
{{{2A/h = m+n}}} Finally, subtract m from both sides.
{{{2A/h-m = n}}}

Answer is:
{{{n = 2A/h-m}}} 

If done correctly, the m does not disappear.