Question 1158355
<pre>

{{{C= expr(1/2)d(n+m)}}}

Multiply through by 2

{{{2*C= 2*expr(1/2)d(n+m)}}}

{{{2*C= cross(2)*expr(1/cross(2))d(n+m)}}}

{{{2C= d(n+m)}}}

Distribute on the right

{{{2C=dn+dm}}}

Subtract dn from both sides

{{{2C-dn=dm}}}

Divide both sides by d

{{{(2C-dn)/d=m}}}

Edwin</pre>