Posted by Sharon on .
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.

Algebra 
Reiny,
width  x
length  x+16
solve
x(x+16) = 420
(it factors quite nicely) 
Algebra 
Henry,
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.