Question 906477
For a triangle,
{{{A=(1/2)bh}}}
{{{(1/2)b(b-3)=20}}}
{{{b(b-3)=40}}}
{{{b^2-3b=40}}}
{{{b^2-3b-40=0}}}
{{{(b-8)(b+5)=0}}}
Only positive solution works here,
{{{b-8=0}}}
{{{b=8}}}
Then,
{{{h=8-3}}}
{{{h=5}}}