Hello there. To solve this question, we have to remember some properties about solving equations for a variable.
Given the following equation:
[tex]A=lw+wh+lh[/tex]We want to solve it for w.
First, notice we can group some factors
[tex]A=w\cdot(l+h)+lh[/tex]Subtract lh on both sides of the equation
[tex]A-lh=w\cdot(l+h)[/tex]Assuming l + h is not equal to zero, divide both sides of the equation by this factor
[tex]w=\dfrac{A-lh}{l+h}[/tex]This is the answer to this question.
