the length of a rectangle is 3 centimeters less than five times its width. its area is 14 centimeters. what are the dimensions of the rectangle?
the length of a rectangle is 3 centimeters less than five times its width. its area is 14 centimeters.
2 Answers
the length of a rectangle is 3 centimeters less than five times its width. its area is 14 centimeters. what are the dimensions of the rectangle?
Let w = width
then
5w-3 = length
w(5w-3) = 14
5w^2-3w = 14
5w^2-3w-14=0
(5w+7)(w-2) = 0
w = {-7/5, 2}
throw out the negative solution leaving
w = 2 centimeters
length:
5w-3 =5(2)-3 =10-3 = 7 centimeters
To express this as an equation, let L represents length and w=width. The length of a rectangle is 3cm less than 5 times its width. This tells us that 3 will be subtracted from 5w. So,
L= 5w-3. Next the area is 14cm and since the area of a rectangle is length*width, it will be expressed as
14=L*w and since L=5w-3
14= (5w-3)*w
14=5w2-3w
5w2-3w-14=0
(5w+7)(w-2)=0
w= -7/5cm or 2cm but the measurement cannot be negative so we will consider 2 instead.
To find length:
L= 5(2)-3
L=10-3
L=7cm.


