Function

Algebra Level 2

If f( x^2 - 5x + 7 ) = x-1 ; then what is summation of all possible value of f(1) ?

0 5 4 3

Arifuzzaman Faisal by Arifuzzaman Faisal , 28, Bangladesh

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3 solutions

As, x^2 - 5x + 7 = 1

or, x^2 - 5x + 6 = 0

or, (x-2)(x-3) = 0

therefore, x = 2,3

so, f(1) = 2-1 = 1 [when x = 2]

and f(1) = 3-1 = 2 [when x = 3]

So, answer is: 1+2=3

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Robin Kashyap
May 6, 2017

x^2- 5x +7 = 1 x= 2,3 So, f(1)=2-1, 3-1 =1,2 So required sum is 1+2=3

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Shahidul Islam
Nov 17, 2015

x^2-5x+7=x-1

> x^2-5x+7-x+1=0 >x^2-6x+8=0 ; f(1)=1-6+8=3

0 Helpful 0 Interesting 0 Brilliant 0 Confused

x^2-5x+7=x-1 is it true ? i think not.... x^2-5x+7=x-1 for this function then for f(x) = x-1; x = x-1 will be true. hope this make your sense.

Arifuzzaman Faisal - 5 years, 6 months ago

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Sorry.... f(x^2......) i just missed the f here, i saw x^2..... =x-1. :)

Shahidul Islam - 5 years, 6 months ago

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