Question

The area of a rectangle is 14 m2 , and the length of the rectangle is 3 m less than double the width. find the dimensions of the rectangle.

Answer 1

width =3.5, length = 4

Let's make a few equations to summarize what we know.:
a = 14
l = 2w -3
a = wl

Now let's substitute the expression for l into the expression for area and solve.
a = w(2w - 3)
a = 2w^2 - 3w
14 = 2w^2 - 3w

0 = 2w^2 - 3w - 14

which factors into
(2w - 7) (w + 2)

Solving for w
2w - 7 = 0
2w = 7
w = 3.5

w+2 = 0
w = -2

So w can be either 3.5 or -2. Since a negative width doesn't make sense, w = 3.5

Let's verify
w = 3.5
l = 2w - 3
l = 2*3.5 - 3
l = 7 - 3
l = 4
a = wl
a = 3.5 * 4
a = 14

So the width is 3.5 and the length is 4.