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Exercise 537Algebra › PolynomialsHigh schoolAdded 3 Nov 2026

Euclidean division

#Euclidean division#quotient#remainder

Statement

Perform the Euclidean division of A(X)=X4−3X3+2X2−X+5A(X)=X^4-3X^3+2X^2-X+5 by B(X)=X2−2X+1B(X)=X^2-2X+1.

Hint

Long division: at each step, eliminate the leading term of the current remainder.

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Solution

First step. X4/(X2)=X2X^4/(X^2)=X^2. Multiply: X2(X2−2X+1)=X4−2X3+X2X^2(X^2-2X+1)=X^4-2X^3+X^2. Subtract from AA:
A−X2B=−X3+X2−X+5.A-X^2B=-X^3+X^2-X+5.

Second step. −X3/(X2)=−X-X^3/(X^2)=-X. Multiply: −X(X2−2X+1)=−X3+2X2−X-X(X^2-2X+1)=-X^3+2X^2-X. Subtract:
(−X3+X2−X+5)−(−X3+2X2−X)=−X2+5.(-X^3+X^2-X+5)-(-X^3+2X^2-X)=-X^2+5.

Third step. −X2/(X2)=−1-X^2/(X^2)=-1. Multiply: −(X2−2X+1)=−X2+2X−1-(X^2-2X+1)=-X^2+2X-1. Subtract:
(−X2+5)−(−X2+2X−1)=−2X+6.(-X^2+5)-(-X^2+2X-1)=-2X+6.

Conclusion. Quotient Q(X)=X2−X−1Q(X)=X^2-X-1, remainder R(X)=−2X+6R(X)=-2X+6. Check: A=BQ+RA=BQ+R.