Why make stupid calcul when

thinking a little more, you would get simple and pretty solution?!

Just have a look on your ugly equation

-b/9(-b/9(x-5)^2+b-5)^2+b=0, when you put x=5, you get

-b/9(b-5)^2+b=0, (and replace b by x, you will get EXACTLY f(x)=0)

then find b=2, while we knew already f(2)=0, a little stupid, right?

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if you know thinking math and use your brain and knowledge intelligently,

5 is unique root of ff(x) ==>if f(b)=f(5), b=5, you can get directly the other root of f(x), without knowing the expression of f(x)

 

所有跟帖： 

• You totally misunderstanding me, f(x)=a(X-5)^2+b,why b=2? you te -jinjing- ♀ (37 bytes) () 07/15/2011 postreply 18:04:50

• you tell me,please,not 8. -jinjing- ♀ (0 bytes) () 07/15/2011 postreply 18:07:08

• Ms. Kang has explained, her explanation is not as clear as you d -15少- ♂ (461 bytes) () 07/16/2011 postreply 06:30:03

• Why f(8)=0?Cs we use a Thm, It is unknow for most people here. -jinjing- ♀ (493 bytes) () 07/16/2011 postreply 08:19:30

• You like calcul -15少- ♂ (329 bytes) () 07/16/2011 postreply 09:10:20

• 回复：You totally misunderstanding me, f(x)=a(X-5)^2+b,why b=2? you -15少- ♂ (1365 bytes) () 07/16/2011 postreply 06:09:01