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The length of a rectangle is 8 less than 5 time it's width. The width is increased by three while the length is unchanged. Using a as the variable, express the change in area in terms of a
Im not quite sure what is being asked. Are we simply supposed to calculate the area? If that is the case i end up getting 2(5w - 8) + 2(w + 3) my books says 15a - 24 :confused:
You must calculate the difference in area between the 'before' and the 'after' situations.
Before the change:
l = 5w - 8
A = w*l
After:
l' = l+3
w' = w
A' = w'*l'
The exercise asks for A'-A.
This part doesn't make sense, there is no a mentioned anywhere. Unless your book uses a as a standard notation for length, width or area.Quote:
Using a as the variable, express the change in area in terms of a
Yeah i mean the wording is crap. No wonder people get confused when taking math tests. :D
The length of a rectangle is 8 less than 5 time it's width. a = l * w
(5w-8) * w
The width is increased by three while the length is unchanged.
(5w - 8) * (w + 3)
So we should end up with. (5w-8)(w+3) - (5w-8)w
6w + 15 w -8w -24 -(6w - 8w)
6w + 15w -8w -24 -6w + 8w
15w - 24
I think that's it. Thanks for the help. :)