Polynomial Function

Algebra Level 3

A third-degree polynomial P ( x ) P(x) , satisfies P ( 0 ) = 3 P(0)= -3 and P ( 1 ) = 4 P(1)= 4 . When P ( x ) P(x) is divided by x 2 + x + 1 x^{2}+ x+ 1 , the remainder is 2 x 1 2x -1 . What is the quotient when P ( x ) P(x) is divided by x 2 + x + 1 x^2 + x + 1 ?

x 6 x-6 3 x 2 3x- 2 x 2 x -2 3 x 1 3x-1

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1 solution

Chew-Seong Cheong
Apr 28, 2016

Let the quotient be Q ( x ) = a x + b Q(x) =ax+b , then we have:

P ( x ) = ( x 2 + x + 1 ) ( a x + b ) + 2 x 1 P ( 0 ) = ( 1 ) ( b ) 1 3 = b 1 b = 2 P ( 1 ) = ( 3 ) ( a 2 ) + 2 1 4 = 3 a 5 a = 3 \begin{aligned} P(x) & =(x^2 +x+1)(ax+b)+2x-1 \\ P(0) & =(1)(b)-1 \\ - 3&=b-1 \\ \implies b & =-2 \\ P(1 ) & =(3)(a-2)+2-1 \\ 4&=3a-5 \\ \implies a&=3 \end{aligned}

Therefore, Q ( x ) = 3 x 2 Q(x) =\boxed {3x-2}

The solution seems to be formatted incorrectly.

Krutarth Patel - 1 month, 3 weeks ago

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Thanks. I think it was caused by the changing of LaTex version.

Chew-Seong Cheong - 1 month, 3 weeks ago

I can see it has been updated. Thanks for the great solution.

Krutarth Patel - 1 month, 3 weeks ago

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