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If the zeros of the polynomial f(x) = x^...

If the zeros of the polynomial `f(x) = x^(3) - 3x^(2) - 6x +8` are of the form a-b,a,a + b, find all the zeros.

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To find the zeros of the polynomial \( f(x) = x^3 - 3x^2 - 6x + 8 \) given that the zeros are of the form \( a-b, a, a+b \), we will follow these steps: ### Step 1: Define the zeros Let the zeros be: - \( \alpha = a - b \) - \( \beta = a \) - \( \gamma = a + b \) ### Step 2: Use the sum of the zeros According to Vieta's formulas, the sum of the zeros of the polynomial \( f(x) = x^3 + bx^2 + cx + d \) is given by: \[ \alpha + \beta + \gamma = -\frac{\text{coefficient of } x^2}{\text{coefficient of } x^3} \] For our polynomial, this is: \[ \alpha + \beta + \gamma = -\frac{-3}{1} = 3 \] Substituting the values of the zeros: \[ (a - b) + a + (a + b) = 3 \] This simplifies to: \[ 3a = 3 \implies a = 1 \] ### Step 3: Use the product of the zeros The product of the zeros is given by: \[ \alpha \cdot \beta \cdot \gamma = -\frac{\text{constant term}}{\text{coefficient of } x^3} \] For our polynomial, this is: \[ \alpha \cdot \beta \cdot \gamma = -\frac{8}{1} = -8 \] Substituting the values of the zeros: \[ (a - b) \cdot a \cdot (a + b) = -8 \] Substituting \( a = 1 \): \[ (1 - b) \cdot 1 \cdot (1 + b) = -8 \] This simplifies to: \[ (1 - b)(1 + b) = -8 \] \[ 1 - b^2 = -8 \implies b^2 = 9 \implies b = 3 \text{ or } b = -3 \] ### Step 4: Find the zeros Now we will find the zeros for both values of \( b \). **Case 1: \( b = 3 \)** - \( \alpha = 1 - 3 = -2 \) - \( \beta = 1 \) - \( \gamma = 1 + 3 = 4 \) So the zeros are \( -2, 1, 4 \). **Case 2: \( b = -3 \)** - \( \alpha = 1 - (-3) = 4 \) - \( \beta = 1 \) - \( \gamma = 1 + (-3) = -2 \) So the zeros are \( 4, 1, -2 \). ### Conclusion In both cases, the zeros are the same: \( -2, 1, 4 \). ### Final Answer The zeros of the polynomial \( f(x) = x^3 - 3x^2 - 6x + 8 \) are \( -2, 1, 4 \). ---
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