Question 157320
The area for a triangle is,
{{{A[t]=(1/2)bh}}}
where b is the base and h is the height.
{{{A[t]=(1/2)bh=18}}}
{{{(1/2)(h+5)h=18}}}
{{{(h+5)h=36}}}
{{{h^2+5h=36}}}
{{{h^2+5h-36=0}}}
{{{(h+9)(h-4)=0}}}
Looks like two solutions, let's check.
{{{h+9=0}}}
{{{h=-9}}}
A negative solution would not make sense.
{{{h-4=0}}}
{{{highlight(h)=4}}}
{{{highlight(b)=h+5=5+4=9}}}