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Let P(x)=|(x+1,2,3),(1,x+2,3),(1,2,x+3...

Let
`P(x)=|(x+1,2,3),(1,x+2,3),(1,2,x+3)|` the product of zeros of P(x) is

A

0

B

6

C

`-6`

D

12

Text Solution

AI Generated Solution

The correct Answer is:
To find the product of the zeros of the polynomial \( P(x) = |(x+1, 2, 3), (1, x+2, 3), (1, 2, x+3)| \), we will first compute the determinant and then identify the product of its roots. ### Step 1: Calculate the Determinant The determinant \( P(x) \) can be calculated using the formula for a 3x3 determinant: \[ P(x) = \begin{vmatrix} x+1 & 2 & 3 \\ 1 & x+2 & 3 \\ 1 & 2 & x+3 \end{vmatrix} \] Using the determinant formula for a 3x3 matrix: \[ \text{det}(A) = a(ei - fh) - b(di - fg) + c(dh - eg) \] where the matrix is: \[ \begin{bmatrix} a & b & c \\ d & e & f \\ g & h & i \end{bmatrix} \] ### Step 2: Apply the Determinant Formula Here, we have: - \( a = x+1, b = 2, c = 3 \) - \( d = 1, e = x+2, f = 3 \) - \( g = 1, h = 2, i = x+3 \) Now substituting into the determinant formula: \[ P(x) = (x+1)((x+2)(x+3) - 3 \cdot 2) - 2(1 \cdot (x+3) - 3 \cdot 1) + 3(1 \cdot 2 - 1 \cdot (x+2)) \] ### Step 3: Simplify Each Term 1. **Calculate \( (x+2)(x+3) - 6 \)**: \[ (x+2)(x+3) = x^2 + 5x + 6 \implies (x^2 + 5x + 6 - 6) = x^2 + 5x \] 2. **Calculate \( 2(1 \cdot (x+3) - 3) \)**: \[ 1 \cdot (x+3) - 3 = x + 3 - 3 = x \implies -2x \] 3. **Calculate \( 3(2 - (x+2)) \)**: \[ 2 - (x+2) = 2 - x - 2 = -x \implies 3(-x) = -3x \] ### Step 4: Combine the Results Now combine all the parts together: \[ P(x) = (x+1)(x^2 + 5x) - 2x - 3x \] \[ = (x+1)(x^2 + 5x) - 5x \] Expanding \( (x+1)(x^2 + 5x) \): \[ = x^3 + 5x^2 + x^2 + 5x = x^3 + 6x^2 + 5x \] Now, substituting back into \( P(x) \): \[ P(x) = x^3 + 6x^2 + 5x - 5x = x^3 + 6x^2 \] ### Step 5: Identify the Coefficients The polynomial can be rewritten as: \[ P(x) = x^3 + 6x^2 + 0x + 0 \] ### Step 6: Find the Product of the Zeros For a cubic polynomial \( ax^3 + bx^2 + cx + d \), the product of the roots is given by: \[ \text{Product of roots} = -\frac{d}{a} \] Here, \( a = 1 \) and \( d = 0 \): \[ \text{Product of roots} = -\frac{0}{1} = 0 \] ### Final Answer The product of the zeros of \( P(x) \) is **0**. ---
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