Difference between revisions of "1974 AHSME Problems/Problem 4"

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<math> \mathrm{(A)\ } 0 \qquad \mathrm{(B) \ }1 \qquad \mathrm{(C) \  } 49 \qquad \mathrm{(D) \  } 50 \qquad \mathrm{(E) \  }51  </math>
 
<math> \mathrm{(A)\ } 0 \qquad \mathrm{(B) \ }1 \qquad \mathrm{(C) \  } 49 \qquad \mathrm{(D) \  } 50 \qquad \mathrm{(E) \  }51  </math>
  
==Solution==
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==Solution 1==
 
From the [[Remainder Theorem]], the remainder when <math> x^{51}+51 </math> is divided by <math> x+1 </math> is <math> (-1)^{51}+51=-1+51=50, \boxed{\text{D}} </math>.
 
From the [[Remainder Theorem]], the remainder when <math> x^{51}+51 </math> is divided by <math> x+1 </math> is <math> (-1)^{51}+51=-1+51=50, \boxed{\text{D}} </math>.
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==Solution 2==
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Notice that <math>x^{51}+51</math> is equal to <math>(x^{51}+1)+50</math>. Since <math>x^51+1=(x+1)(x^{50}-x^{49}+ \ldots +x^2 - x + 1)</math>, this part of the polynomial is divisible by <math>x+1</math>. Thus, the remainder is <math>\boxed{\textbf{(D)}~50}</math>.
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~ cxsmi
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== Video Solution by OmegaLearn ==
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https://youtu.be/Dp-pw6NNKRo?t=256
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~ pi_is_3.14
  
 
==See Also==
 
==See Also==
 
{{AHSME box|year=1974|num-b=3|num-a=5}}
 
{{AHSME box|year=1974|num-b=3|num-a=5}}
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[[Category:Introductory Algebra Problems]]
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{{MAA Notice}}

Latest revision as of 00:17, 9 June 2024

Problem

What is the remainder when $x^{51}+51$ is divided by $x+1$?

$\mathrm{(A)\ } 0 \qquad \mathrm{(B) \ }1 \qquad \mathrm{(C) \  } 49 \qquad \mathrm{(D) \  } 50 \qquad \mathrm{(E) \  }51$

Solution 1

From the Remainder Theorem, the remainder when $x^{51}+51$ is divided by $x+1$ is $(-1)^{51}+51=-1+51=50, \boxed{\text{D}}$.

Solution 2

Notice that $x^{51}+51$ is equal to $(x^{51}+1)+50$. Since $x^51+1=(x+1)(x^{50}-x^{49}+ \ldots +x^2 - x + 1)$, this part of the polynomial is divisible by $x+1$. Thus, the remainder is $\boxed{\textbf{(D)}~50}$.

~ cxsmi

Video Solution by OmegaLearn

https://youtu.be/Dp-pw6NNKRo?t=256

~ pi_is_3.14

See Also

1974 AHSME (ProblemsAnswer KeyResources)
Preceded by
Problem 3
Followed by
Problem 5
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All AHSME Problems and Solutions

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