1. **State the problem:**
We want to express the rational function $$\frac{4x^3 - 5x^2 + 3x - 14}{x^2 + 2x - 1}$$ in the form $$Ax + B + \frac{Cx + D}{x^2 + 2x - 1}$$ and find constants $A$, $B$, $C$, and $D$.
2. **Formula and approach:**
Since the degree of the numerator (3) is greater than the degree of the denominator (2), perform polynomial division:
$$\frac{4x^3 - 5x^2 + 3x - 14}{x^2 + 2x - 1} = Ax + B + \frac{Cx + D}{x^2 + 2x - 1}$$
where $Ax + B$ is the quotient and $Cx + D$ is the remainder polynomial of degree less than 2.
3. **Perform polynomial division:**
Divide $4x^3 - 5x^2 + 3x - 14$ by $x^2 + 2x - 1$.
- First term: $4x^3 \div x^2 = 4x$, so $A = 4$.
- Multiply divisor by $4x$: $$4x(x^2 + 2x - 1) = 4x^3 + 8x^2 - 4x$$
- Subtract: $$\left(4x^3 - 5x^2 + 3x - 14\right) - \left(4x^3 + 8x^2 - 4x\right) = -13x^2 + 7x - 14$$
- Next term: $-13x^2 \div x^2 = -13$, so $B = -13$.
- Multiply divisor by $-13$: $$-13(x^2 + 2x - 1) = -13x^2 - 26x + 13$$
- Subtract: $$(-13x^2 + 7x - 14) - (-13x^2 - 26x + 13) = 33x - 27$$
4. **Write the division result:**
$$\frac{4x^3 - 5x^2 + 3x - 14}{x^2 + 2x - 1} = 4x - 13 + \frac{33x - 27}{x^2 + 2x - 1}$$
5. **Identify constants:**
$$A = 4, \quad B = -13, \quad C = 33, \quad D = -27$$
**Final answer:**
$$\boxed{A=4, B=-13, C=33, D=-27}$$
Partial Fraction 2E72A0
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