Algebra
posted by Sharon .
A rectangular counter top is 16 inches longer than it is wide. If the area of the counter top is 420 square inches, find the length and the width.

width  x
length  x+16
solve
x(x+16) = 420
(it factors quite nicely) 
Width = W inches
Length = W + 16 inches.
W(W + 16) = 420
W^2 + 16W  420 = 0
Use Quadratic Formula:
w = (16+ /  sqrt(256 + 1680))/2 =
(16 + 44)/2 = 14 and 30. use W = 14
= Width.
W +16 = 14 + 16 = 30 in. = Length.