Question 965088
Not this, D(h)=7e^-0.3h
but instead
THIS:  D(h)=7e^(-0.3h)


The rendering will give the more standard-like notation, {{{D(h)=7e^(-0.3h)}}}.


Question (a)  is fairly simple.


Question (b):
{{{1=7*e^(-0.3h)}}}
{{{ln(1)=ln(7)+ln(e^(-0.3h))}}}
{{{0=ln(7)-0.3h*1}}}
{{{0.3h=ln(7)}}}
{{{highlight(h=ln(7)/(0.3))}}}