Step 1 · Divide the leading terms
x³ ÷ x = x². Write x² directly above the x³ column.
| x² | ||||
| x−2 | x³ | −4x² | +x | +6 |
Divide polynomials step by step, build the quotient, and verify the remainder.
Select a method and one of four examples. Reveal one step at a time and follow how the quotient is built.
x³ ÷ x = x². Write x² directly above the x³ column.
| x² | ||||
| x−2 | x³ | −4x² | +x | +6 |
Multiply x²(x−2)=x³−2x². Keep like powers in the same columns, then subtract.
| x² | ||||
| x−2 | x³ | −4x² | +x | +6 |
| − | x³ | −2x² | ||
| −2x² | +x |
−2x² ÷ x = −2x. Place −2x above the x² column. Multiply, subtract, and bring down +6.
| x² | −2x | |||
| x−2 | x³ | −4x² | +x | +6 |
| − | x³ | −2x² | ||
| −2x² | +x | |||
| − | −2x² | +4x | ||
| −3x | +6 |
−3x ÷ x = −3. Place −3 above the x column, multiply, and subtract.
| x² | −2x | −3 | ||
| x−2 | x³ | −4x² | +x | +6 |
| − | x³ | −2x² | ||
| −2x² | +x | |||
| − | −2x² | +4x | ||
| −3x | +6 | |||
| − | −3x | +6 | ||
| 0 |
Quotient: x²−2x−3 Remainder: 0
2x³ ÷ x = 2x². Place 2x² directly above the 2x³ column.
| 2x² | ||||
| x+3 | 2x³ | +3x² | −11x | −6 |
2x²(x+3)=2x³+6x². Align the equal powers before subtracting.
| 2x² | ||||
| x+3 | 2x³ | +3x² | −11x | −6 |
| − | 2x³ | +6x² | ||
| −3x² | −11x |
−3x² ÷ x = −3x. Place −3x above the x² column, multiply, subtract, and bring down −6.
| 2x² | −3x | |||
| x+3 | 2x³ | +3x² | −11x | −6 |
| − | 2x³ | +6x² | ||
| −3x² | −11x | |||
| − | −3x² | −9x | ||
| −2x | −6 |
−2x ÷ x = −2. Place −2 above the x column, multiply, and subtract.
| 2x² | −3x | −2 | ||
| x+3 | 2x³ | +3x² | −11x | −6 |
| − | 2x³ | +6x² | ||
| −3x² | −11x | |||
| − | −3x² | −9x | ||
| −2x | −6 | |||
| − | −2x | −6 | ||
| 0 |
Quotient: 2x²−3x−2 Remainder: 0
The x³ term and x term are missing. Write them with zero coefficients before dividing.
x⁴+0x³+x²+0x+3
| x³ | |||||
| x−3 | x⁴ | +0x³ | +x² | +0x | +3 |
x⁴ ÷ x=x³. Multiply x³(x−3)=x⁴−3x³ and subtract.
| x³ | |||||
| x−3 | x⁴ | +0x³ | +x² | +0x | +3 |
| − | x⁴ | −3x³ | |||
| 3x³ | +x² |
3x³ ÷ x=3x². Multiply 3x²(x−3)=3x³−9x² and subtract.
| x³ | +3x² | ||||
| x−3 | x⁴ | +0x³ | +x² | +0x | +3 |
| − | x⁴ | −3x³ | |||
| 3x³ | +x² | ||||
| − | 3x³ | −9x² | |||
| 10x² | +0x |
10x² ÷ x=10x. Multiply 10x(x−3)=10x²−30x and subtract.
| x³ | +3x² | +10x | |||
| x−3 | x⁴ | +0x³ | +x² | +0x | +3 |
| − | x⁴ | −3x³ | |||
| 3x³ | +x² | ||||
| − | 3x³ | −9x² | |||
| 10x² | +0x | ||||
| − | 10x² | −30x | |||
| 30x | +3 |
30x ÷ x=30. Multiply 30(x−3)=30x−90 and subtract.
| x³ | +3x² | +10x | +30 | ||
| x−3 | x⁴ | +0x³ | +x² | +0x | +3 |
| − | x⁴ | −3x³ | |||
| 3x³ | +x² | ||||
| − | 3x³ | −9x² | |||
| 10x² | +0x | ||||
| − | 10x² | −30x | |||
| 30x | +3 | ||||
| − | 30x | −90 | |||
| 93 |
Quotient: x³+3x²+10x+30 Remainder: 93
Arrange from the greatest exponent to the constant before dividing.
−7x⁴+5x³+x²+3x−3
| 2x+7 | −7x⁴ | +5x³ | +x² | +3x | −3 |
−7x⁴ ÷ 2x=−x³. Multiply by 2x+7 and subtract.
| −x³ | |||||
| 2x+7 | −7x⁴ | +5x³ | +x² | +3x | −3 |
| − | −7x⁴ | −x³ | |||
| x³ | +x² |
x³ ÷ 2x=+x². Multiply and subtract.
| −x³ | +x² | ||||
| 2x+7 | −7x⁴ | +5x³ | +x² | +3x | −3 |
| − | −7x⁴ | −x³ | |||
| x³ | +x² | ||||
| − | x³ | +x² | |||
| −x² | +3x |
−x² ÷ 2x=−x. Multiply, subtract, and bring down −3.
| −x³ | +x² | −x | |||
| 2x+7 | −7x⁴ | +5x³ | +x² | +3x | −3 |
| − | −7x⁴ | −x³ | |||
| x³ | +x² | ||||
| − | x³ | +x² | |||
| −x² | +3x | ||||
| − | −x² | −x | |||
| x | −3 |
x ÷ 2x=+. Multiply and subtract to obtain the remainder.
| −x³ | +x² | −x | + | ||
| 2x+7 | −7x⁴ | +5x³ | +x² | +3x | −3 |
| − | −7x⁴ | −x³ | |||
| x³ | +x² | ||||
| − | x³ | +x² | |||
| −x² | +3x | ||||
| − | −x² | −x | |||
| x | −3 | ||||
| − | x | + | |||
| − |
Quotient: −x³+x²−x+ Remainder: −
x−2 means c=2. Write the coefficients 1, −4, 1, 6. Include 0 for any missing term.
Bring down 1. Multiply 1×2=2 and place 2 under −4.
−4+2=−2. Then −2×2=−4; 1+(−4)=−3; −3×2=−6.
6+(−6)=0. The first three bottom entries form x²−2x−3; the last entry is the remainder.
Quotient: x²−2x−3 Remainder: 0
x−2 gives c=2. Use coefficients 2, −3, 4, −5.
Bring down 2. Multiply 2×2=4. Add −3+4=1.
Multiply 1×2=2. Add 4+2=6. Multiply 6×2=12.
Add −5+12=7. The quotient coefficients are 2, 1, 6; the final entry is the remainder.
Quotient: 2x²+x+6 Remainder: 7
The x³ term and x term are missing. Use 0 as a placeholder for each one: 1, 0, 1, 0, 3. Since x−3=x−c, use c=3.
Bring down 1. Multiply 1×3=3 and write 3 below the first zero. Add 0+3=3.
Multiply 3×3=9. Add 1+9=10. Then multiply 10×3=30 and add 0+30=30.
Multiply 30×3=90. Add 3+90=93. The first four bottom entries are the quotient coefficients; the last entry is the remainder.
Quotient: x³+3x²+10x+30 Remainder: 93
First write the dividend in standard form: −7x⁴+5x³+x²+3x−3. Ordinary synthetic division needs x−c, so factor the divisor: 2x+7=2(x+7/2)=2[x−(−7/2)]. Use c=−7/2.
Bring down −7. Multiply (−7)(−)=. Add 5+49/2=59/2.
Multiply (−)=− and add 1 to obtain −. Then multiply again to obtain and add 3 to obtain .
Multiply (−)=−. Add −3 to get −. This last entry is the remainder.
The synthetic row first gives the quotient for x+7/2: −7x³+x²−x+. Because 2x+7 is twice x+7/2, divide every quotient coefficient by 2. The remainder does not change.
Synthetic quotient for x+7/2: −7x³+x²−x+
Final quotient for 2x+7: −x³+x²−x+
Remainder: −
For P(x)=2x³−3x²+4x−5 divided by x−2, the theorem says the remainder is P(2).
P(2)=2(2)³−3(2)²+4(2)−5
=16−12+8−5=7
The computed value 7 matches the last entry in Synthetic Example 2. Therefore the quotient is 2x²+x+6 and the remainder is 7.