Find area of a rectangle if length is given

[tayross]

if the length of a rectangle = x,
show that the area of the rectangle is given by A = 8x - x[2]

 

[CompuChip]

You need some more information, like that the width of the rectangle is 8 - x.

 

[tayross]

yeah that's what i thought
the answer says

if the length = x then the width equals 1/2 (16 - 2x) = 8 - x

area = length x width

a = x (8 - x )
= 8x - x [2]

do not understand this at all blah!

 

[CompuChip]

Neither do I, there must be some information you are not giving us.
Please post the entire question.

Other than that, let us assume for a moment that we know that the length of a rectangle is x and its width is 8 - x.
Then do you agree that its area must be x(8 - x)?
Do you see how opening the brackets gives 8x - x²?