f(x)=x-10

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Junior | Next Rank: 30 Posts
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f(x)=x-10

by Hano » Thu Dec 06, 2007 9:56 pm
The function f is defined by f(x) = √x – 10 for all positive numbers x. If u = f(t) for some positive numbers t and u. What is t in terms of u?
A. √(u+10)
B. (√u + 10)^2
C. √(u^2+10)
D. (u + 10)^2
E. (u^2 + 10)


please explain

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by seekmba » Fri Dec 07, 2007 12:31 am
f(x) = √x ? 10

I think this ? is - sign
so f(t) = squarert(t) - 10 = u
so suqarert(t) = u+10
ot t= (u+10)^2

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by Hano » Fri Dec 07, 2007 6:07 pm
I cant really read what was explained.

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by gian-28 » Sat Dec 08, 2007 3:42 pm
The function f is defined by f(x) = √x – 10 for all positive numbers x. If u = f(t) for some positive numbers t and u. What is t in terms of u?


If u = f(t) for some positive numbers t and u, then u= √t – 10. now we'll have to solve for t.
u^2=t-10
u^2+10=t... which is what E tells us.

I hope that's easier to read and I hope it's correct

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by mleviko » Sat Dec 08, 2007 10:21 pm
u = sqr(t) - 10
u + 10 = sqr(t)
(u+10)^2 = t

ans D

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ouuupppppps

by gian-28 » Sun Dec 09, 2007 3:02 am
oupppss sorry, the answer is D. I mistook √x – 10 for √(x-10).