Question 884839
Examining the description gives nothing to relate dimension of the small and large monitors.


Try assigning variables.
Small:
x and y width and length
Large:
w and L width and length


Develop expressions and equations:
{{{highlight_green(xy=wL-80)}}};  {{{highlight_green(L=w+5)}}};  {{{highlight_green(xy=70)}}}.


The two area equations give something to solve.
{{{wL-80=xy=70}}}
{{{wL-80=70}}}
{{{wL=70+80}}}
{{{wL=150}}}-----The area for the current large monitor.


Substitute the formula transcribed for L into that area equation.
{{{w(w+5)=150}}}
{{{w^2+5w-150=0}}}
{{{(w+15)(w-10)=0}}}
The meaningful value is {{{highlight(w=10)}}}.
{{{highlight(L=15)}}}.
Recall as assigned, w and L are for the larger monitor.