Answer:
[tex]l= \frac{A}{2h} -w[/tex]
Step-by-step explanation:
The question is not correct (particularly the expression for the area)
A=2lh+2wh
Now we are expected to solve for l, that is we are going to make l subject of the formula, we have
let us take the second term on the RHS to the LHS
[tex]A-2wh= 2lh[/tex]
we can now divide both sides by 2h we have
[tex]\frac{A-2wh}{2h} = l\\\\l=\frac{A}{2h} -\frac{2wh}{2h} \\\\l= \frac{A}{2h} -w[/tex]
hence the expression for the length is [tex]l= \frac{A}{2h} -w[/tex]
