This came from a friend of mine who has a math book on hand with a statement that doesn't seem to make sense. Neither of us are in school/college at the moment. This is math for the fun of it.

I've thought long and hard on this and even, at one point, ran into a reference to a barn and 100 feet of fence to section off a rectangular plot using the side of the barn.

I tested out A(x) = xh by itself and substituted h by making it relative to x (x/2 = h or that is to say that the height is 1/2 the width). When looked at it that way, the output for A(x) makes sense for the area. I cannot make sense of the 2 though in A(x) = 2xh.

Most like we're dealing with a function like y=3, when the author saids "area, he is probably referring to a rectangle extending equally on either side of the origin, hence A=2xh, since x is only half the extension.

Either you're not copying what's in this book correctly or the book is unbelievably messed up.

I can begin to follow what they're doing, but then what you have here makes no sense.

We have 100 ft of fencing that will be used to fence in three sides of a rectangle.
From one equation they give -- x + 2h = 100 -- we can conclude that the side parallel to the barn has length x (ft) and the two sides perpendicular to barn each have length h (ft).

Skipping down to the end, you have
x + 2ft = 100 -- that should be x + 2h = 100

So 2h = 100 - x -- this is OK
Then you have h = 50 -- -- this is wrong

Copied as in "cut and paste"? (I'm not going to look through that whole thing to find what you are referencing.

If it was cut and paste, then why would you interpret the answer provided as "shooting the messenger"? Since the response was "if you have copied it correctly then the book is messed up". Why not respond, "thanks for confirming for me that the book is messed up"

Thank you all for your efforts. I too found that example of the fence in a different website full of examples. My friend had the very same example out of her book that she tried to work. I also saw how you cannot have an answer of 50 for x since that means you have 50 on one side and the other and a big, open hole going out into the open.