Question 401591
express the perimeter P of the rectangle as a function of the Length L if the width of the rectangle is twice its length.

Sol'n:
P = 2L + 2W
since: W = 2L
thus, substitute W = 0.5 to P.
P = 2L + 2(2W)
P = 2L + 4L
P = 6L ---answer 

^_^