math help? 10 pts!?

2008-07-28 11:46 am

How do i work this out?

http://img139.imageshack.us/my.php?image=ddrb9.gif

Thanks in advance.

更新1:

i've tried but it doesn't fit. Say h was 5 and w was 10. It doesn't exactly work out. i'm just wondering any other ways to figure it out.

更新2:

ANOTHER QUESTION: Why does it have a negative sign in it? does this have to do with it moving across the equals sign?

回答 (5)

2008-07-28 11:56 am

✔ 最佳答案

simple algrebra:

(w/h) = ((w+h)/w)
w = (h(w+h)/w)
w^2 = h(w+h)
w^2 = hw +h^2
w^2 - hw = h^2

Answer is D

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2008-07-28 7:00 pm

by solving or simplifying that equation, you will get the form,
w^2-h^2=wh
or,
w^2-wh=h^2
so my answer is option no D

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2008-07-28 6:58 pm

w/h = (w + h)/w
w^2/h = w + h
w^2 = h(w + h)
w^2 = wh + h^2
w^2 - wh = h^2
(answer D)

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2008-07-28 6:53 pm

D.

Cross multiply and you'll discover that it's the answer you're after.

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2008-07-28 6:52 pm

(w/h) = (w+h)/w
so, w^2 = wh + h^2 by cross multiplying. Now can you decide?
or w^2 - h^2 = wh is better?

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