Solve.
-The width of a rectangle is 6 kilometers less than twice its length. If its area is 140 square kilometers, find the dimensions of the rectangle.
A) length $= 10 \mathrm {~km}$, width $= 14 \mathrm {~km}$
B) length $= 3 \mathrm {~km}$, width $= \frac { 140 } { 3 } \mathrm {~km}$
C) width $= 10 \mathrm {~km}$, length $= 14 \mathrm {~km}$
D) length $= 7 \mathrm {~km}$, width $= 8 \mathrm {~km}$

Question

Solve.
-The width of a rectangle is 6 kilometers less than twice its length. If its area is 140 square kilometers, find the dimensions of the rectangle. 
A) length $= 10 \mathrm {~km}$, width $= 14 \mathrm {~km}$
B) length $= 3 \mathrm {~km}$, width $= \frac { 140 } { 3 } \mathrm {~km}$
C) width $= 10 \mathrm {~km}$, length $= 14 \mathrm {~km}$
D) length $= 7 \mathrm {~km}$, width $= 8 \mathrm {~km}$

Quizplus · Accepted Answer

The correct dimensions are found by setting up the equation $l \times w = 140$ and $w = 2l - 6$. Substituting the second equation into the first gives a quadratic equation in terms of $l$, which solves to $l = 10$ km and $w = 14$ km.

Solve -The Width of a Rectangle Is 6 Kilometers Less =10 km= 10 \mathrm {~km}=10 km

Solve
-The Width of a Rectangle Is 6 Kilometers Less $= 10 \mathrm {~km}$