1. **Stating the problem:**
We are given the equation $$D(2x - 1) = A(x^2 - x + 1) + B(x - 2)$$ and need to find the values of constants $A$, $B$, and $D$ that satisfy this identity for all $x$.
2. **Understanding the problem:**
This is a polynomial identity where the left side is a linear polynomial multiplied by $D$, and the right side is a sum of polynomials multiplied by constants $A$ and $B$.
3. **Rewrite the equation:**
$$D(2x - 1) = A(x^2 - x + 1) + B(x - 2)$$
4. **Expand the right side:**
$$A(x^2 - x + 1) + B(x - 2) = A x^2 - A x + A + B x - 2 B$$
5. **Group like terms:**
$$= A x^2 + (-A + B) x + (A - 2 B)$$
6. **Match coefficients with the left side:**
The left side is $$D(2x - 1) = 2 D x - D$$
Since the left side is linear and the right side has a quadratic term $A x^2$, for the identity to hold for all $x$, the coefficient of $x^2$ must be zero:
$$A = 0$$
7. **Substitute $A=0$ back:**
Right side becomes:
$$0 imes x^2 + (-0 + B) x + (0 - 2 B) = B x - 2 B$$
8. **Equate coefficients of $x$ and constant terms:**
From $x$ terms:
$$2 D = B$$
From constant terms:
$$-D = -2 B$$
9. **Solve the system:**
From the constant terms:
$$-D = -2 B \implies D = 2 B$$
From the $x$ terms:
$$2 D = B$$
Substitute $D = 2 B$ into $2 D = B$:
$$2 (2 B) = B \implies 4 B = B \implies 3 B = 0 \implies B = 0$$
Then:
$$D = 2 B = 0$$
10. **Final values:**
$$A = 0, B = 0, D = 0$$
**Answer:**
$$\boxed{A=0, B=0, D=0}$$
Polynomial Identity
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