Question 22286
Simplify:
{{{1/1 + 1/xab + 1/1 + 1/xba}}} First, {{{1/1 = 1}}} and {{{1+1 = 2}}}
{{{2 + 1/xab + 1/xba}}} Now, {{{1/xab = 1/xba}}} and {{{1/xab + 1/xab = 2/xab}}} 
{{{2 + 2/xab}}} Now add the two fractions, common denominator is xab.
{{{2 + 2/xab = (2xab + 2)/xab}}} = {{{2(xab + 1)/xab}}}