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Resolve into partial fractions : (x^(2...

Resolve into partial fractions :
`(x^(2)+7x+11)/((x+2)^(2)(x+3))= (A)/((x+2))+(B)/((x+2)^2)+(C )/(x+3)`.

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The correct Answer is:
To resolve the expression \(\frac{x^2 + 7x + 11}{(x + 2)^2 (x + 3)}\) into partial fractions, we start by expressing it in the form: \[ \frac{x^2 + 7x + 11}{(x + 2)^2 (x + 3)} = \frac{A}{(x + 2)} + \frac{B}{(x + 2)^2} + \frac{C}{(x + 3)} \] ### Step 1: Set up the equation We multiply both sides by the denominator \((x + 2)^2 (x + 3)\) to eliminate the fractions: \[ x^2 + 7x + 11 = A(x + 2)(x + 3) + B(x + 3) + C(x + 2)^2 \] ### Step 2: Expand the right-hand side Now we expand the right-hand side: 1. For \(A(x + 2)(x + 3)\): \[ A(x^2 + 5x + 6) = Ax^2 + 5Ax + 6A \] 2. For \(B(x + 3)\): \[ Bx + 3B \] 3. For \(C(x + 2)^2\): \[ C(x^2 + 4x + 4) = Cx^2 + 4Cx + 4C \] Combining these gives: \[ x^2 + 7x + 11 = (A + C)x^2 + (5A + B + 4C)x + (6A + 3B + 4C) \] ### Step 3: Compare coefficients Now we compare the coefficients of both sides: 1. Coefficient of \(x^2\): \[ A + C = 1 \quad \text{(1)} \] 2. Coefficient of \(x\): \[ 5A + B + 4C = 7 \quad \text{(2)} \] 3. Constant term: \[ 6A + 3B + 4C = 11 \quad \text{(3)} \] ### Step 4: Solve the system of equations We have the system of equations: 1. \(A + C = 1\) 2. \(5A + B + 4C = 7\) 3. \(6A + 3B + 4C = 11\) From equation (1), we can express \(C\) in terms of \(A\): \[ C = 1 - A \quad \text{(4)} \] Substituting (4) into equations (2) and (3): **Substituting into (2):** \[ 5A + B + 4(1 - A) = 7 \] \[ 5A + B + 4 - 4A = 7 \] \[ A + B + 4 = 7 \implies B = 3 - A \quad \text{(5)} \] **Substituting into (3):** \[ 6A + 3(3 - A) + 4(1 - A) = 11 \] \[ 6A + 9 - 3A + 4 - 4A = 11 \] \[ -1A + 13 = 11 \implies -A = -2 \implies A = 2 \] ### Step 5: Find \(B\) and \(C\) Using \(A = 2\) in (4) and (5): From (4): \[ C = 1 - 2 = -1 \] From (5): \[ B = 3 - 2 = 1 \] ### Step 6: Write the final partial fraction decomposition Now substituting \(A\), \(B\), and \(C\) back into the partial fractions: \[ \frac{x^2 + 7x + 11}{(x + 2)^2 (x + 3)} = \frac{2}{(x + 2)} + \frac{1}{(x + 2)^2} - \frac{1}{(x + 3)} \] ### Final Answer Thus, the partial fraction decomposition is: \[ \frac{2}{(x + 2)} + \frac{1}{(x + 2)^2} - \frac{1}{(x + 3)} \]
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