Question 1009763
Draw the picture.  x and y dimensions of the poster.  x for horizontal, y for vertical.


{{{A=xy}}}  for area function;
{{{(x-2*2)(y-2*4)=50}}}


Use the print-type region equation, .... {{{y=50/(x-4)+8}}} and substituting into A, omitting to show the steps here,
{{{highlight_green(A(x)=(50x)/(x-4)+8x)}}}.


Taking derivative of that in preparation to find optimized values,
{{{dA/dx=((x-4)50-50x*1)/(x-4)^2+8}}}
and again omitting further algebra steps for the derivative,...
{{{highlight_green(dA/dx=(8x^2-64x-72)/(x-4)^2)}}}


Set that equal to 0, solve for x, and find corresponding y value.


Focus on the numerator to be set to 0.
{{{8x^2-64x-72=0}}}
{{{x^2-8x-9=0}}}
{{{(x-9)(x+1)=0}}}


The meaningful value for x is {{{highlight(x=9)}}}.


Use that to find y
{{{y=50/(9-4)+8}}}
{{{highlight(y=18)}}}