- Set up polynomial long division: We want to divide the polynomial $x^3 + 3x^2 + 5x + 3$ by $x + 1$. We set this up like a standard long division problem.
```
____________
x + 1 | x^3 + 3x^2 + 5x + 3
```
- Divide the leading terms: Divide the leading term of the dividend ($x^3$) by the leading term of the divisor ($x$). This gives $x^3 / x = x^2$. Write this $x^2$ above the $x^2$ term in the dividend.
```
x^2 ________
x + 1 | x^3 + 3x^2 + 5x + 3
```
- Multiply and subtract: Multiply the quotient term ($x^2$) by the entire divisor ($x + 1$). This gives $x^2(x + 1) = x^3 + x^2$. Write this result below the dividend and subtract it.
```
x^2 ________
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2
```
- Bring down the next term: Bring down the next term of the dividend ($+5x$) to form the new polynomial to work with.
```
x^2 ________
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2 + 5x
```
- Repeat the process: Divide the leading term of the new polynomial ($2x^2$) by the leading term of the divisor ($x$). This gives $2x^2 / x = 2x$. Write this $+2x$ in the quotient.
```
x^2 + 2x ____
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2 + 5x
```
- Multiply and subtract again: Multiply the new quotient term ($2x$) by the divisor ($x + 1$). This gives $2x(x + 1) = 2x^2 + 2x$. Write this below and subtract.
```
x^2 + 2x ____
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2 + 5x
-(2x^2 + 2x)
__________
3x
```
- Bring down the last term: Bring down the last term of the dividend ($+3$).
```
x^2 + 2x ____
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2 + 5x
-(2x^2 + 2x)
__________
3x + 3
```
- Final division step: Divide the leading term of the new polynomial ($3x$) by the leading term of the divisor ($x$). This gives $3x / x = 3$. Write this $+3$ in the quotient.
```
x^2 + 2x + 3
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2 + 5x
-(2x^2 + 2x)
__________
3x + 3
```
- Multiply and subtract one last time: Multiply the new quotient term ($3$) by the divisor ($x + 1$). This gives $3(x + 1) = 3x + 3$. Write this below and subtract.
```
x^2 + 2x + 3
x + 1 | x^3 + 3x^2 + 5x + 3
-(x^3 + x^2)
__________
2x^2 + 5x
-(2x^2 + 2x)
__________
3x + 3
-(3x + 3)
________
0
```
- State the quotient: Since the remainder is 0, the quotient is the polynomial we found above.