The formula for the perimeter of a rectangle is given as;
[tex]P=2w+2l[/tex]To find the formula for the length of the rectangle in terms of the perimeter and the width, let make l the subject of formula.
Firstly subtract 2w from both sides of the formula;
[tex]\begin{gathered} P-2w=2w-2w+2l \\ P-2w=2l \\ 2l=P-2w \end{gathered}[/tex]Then divide both sides of the equation by 2;
[tex]\begin{gathered} \frac{2l}{2}=\frac{P-2w}{2} \\ l=\frac{P-2w}{2} \end{gathered}[/tex]Therefore, the formula that can be used to find the length of a
rectangle in terms of the perimeter and width is;
[tex]l=\frac{P-2w}{2}[/tex]