Question 53800
First simplify the parenthese, then multiply both sides by 3, then subtract 145 from both sides like so:
{{{(72+73+x)/3=72.9}}}
{{{(145+x)/3=72.9}}}
{{{3(145+x)/3=3(72.9)}}}
{{{(cross(3))(145+x)/(cross(3))=218.7}}}
{{{145+x=218.7}}}
{{{-145+145+x=218.7-145}}}
{{{x=73.7}}}
Happy Calculating!