To solve for w, you need to isolate/get the variable "w" by itself in the equation:
P = 2(l + w) Divide 2 on both sides
[tex]\frac{P}{2} =\frac{2(l+w)}{2}[/tex]
[tex]\frac{P}{2} =l+w[/tex] Subtract l on both sides to get "w" by itself
[tex]\frac{P}{2} -l=l-l+w[/tex]
[tex]\frac{P}{2} -l=w[/tex]
