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(x^(3)+3x^(2)+5)/((x-1)(x+2)^2) =1+(a)/(...

`(x^(3)+3x^(2)+5)/((x-1)(x+2)^2) =1+(a)/(x-1)+(b)/(x+2)+(c)/((x+2)^2)`
a, b, c are respectively

A

1,2,3

B

1,-1,3

C

1,-1,-3

D

1,0,3

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To solve the equation \[ \frac{x^3 + 3x^2 + 5}{(x-1)(x+2)^2} = 1 + \frac{a}{x-1} + \frac{b}{x+2} + \frac{c}{(x+2)^2} \] we will find the values of \(a\), \(b\), and \(c\). ### Step 1: Rewrite the Right-Hand Side with a Common Denominator The common denominator for the right-hand side is \((x-1)(x+2)^2\). Thus, we rewrite the right-hand side: \[ 1 + \frac{a}{x-1} + \frac{b}{x+2} + \frac{c}{(x+2)^2} = \frac{(x-1)(x+2)^2 + a(x+2)^2 + b(x-1)(x+2) + c(x-1)}{(x-1)(x+2)^2} \] ### Step 2: Expand the Numerator Now, we need to expand the numerator: 1. Expand \((x-1)(x+2)^2\): \[ (x-1)(x^2 + 4x + 4) = x^3 + 4x^2 + 4x - x^2 - 4x - 4 = x^3 + 3x^2 - 4 \] 2. Expand \(a(x+2)^2\): \[ a(x^2 + 4x + 4) = ax^2 + 4ax + 4a \] 3. Expand \(b(x-1)(x+2)\): \[ b(x^2 + x - 2) = bx^2 + bx - 2b \] 4. Expand \(c(x-1)\): \[ cx - c \] Combining all these, the numerator becomes: \[ x^3 + 3x^2 - 4 + ax^2 + 4ax + 4a + bx^2 + bx - 2b + cx - c \] ### Step 3: Combine Like Terms Combining like terms gives us: \[ x^3 + (3 + a + b)x^2 + (4a + b + c)x + (4a - 2b - c) \] ### Step 4: Set the Numerators Equal Now, we set the numerator of the left-hand side equal to the numerator of the right-hand side: \[ x^3 + 3x^2 + 5 = x^3 + (3 + a + b)x^2 + (4a + b + c)x + (4a - 2b - c) \] ### Step 5: Equate Coefficients From the above equation, we can equate the coefficients: 1. Coefficient of \(x^2\): \[ 3 + a + b = 3 \implies a + b = 0 \quad (1) \] 2. Coefficient of \(x\): \[ 4a + b + c = 0 \quad (2) \] 3. Constant term: \[ 4a - 2b - c = 5 \quad (3) \] ### Step 6: Solve the System of Equations From equation (1): \[ b = -a \quad (4) \] Substituting (4) into (2): \[ 4a - a + c = 0 \implies 3a + c = 0 \implies c = -3a \quad (5) \] Substituting (4) and (5) into (3): \[ 4a - 2(-a) - (-3a) = 5 \implies 4a + 2a + 3a = 5 \implies 9a = 5 \implies a = \frac{5}{9} \] Now substituting \(a\) back into (4) to find \(b\): \[ b = -\frac{5}{9} \] And substituting \(a\) into (5) to find \(c\): \[ c = -3 \cdot \frac{5}{9} = -\frac{15}{9} = -\frac{5}{3} \] ### Final Values Thus, the values of \(a\), \(b\), and \(c\) are: \[ a = \frac{5}{9}, \quad b = -\frac{5}{9}, \quad c = -\frac{5}{3} \]
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