width --- x
length --- x+16
solve
x(x+16) = 420
(it factors quite nicely)
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.
2 answers
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.
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.
2 answers