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Find the value of k such that 3x^(2)+2kx...

Find the value of `k` such that `3x^(2)+2kx+x-k-5` has the sum of zeros as half of their product.

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To find the value of \( k \) such that the polynomial \( 3x^2 + 2kx + x - k - 5 \) has the sum of its zeros equal to half of their product, we will follow these steps: ### Step 1: Rewrite the polynomial in standard form The given polynomial is: \[ 3x^2 + 2kx + x - k - 5 \] We can combine the terms involving \( x \): \[ 3x^2 + (2k + 1)x - (k + 5) \] Thus, we have: \[ A = 3, \quad B = 2k + 1, \quad C = -k - 5 \] ### Step 2: Use the formulas for the sum and product of the roots For a quadratic polynomial \( Ax^2 + Bx + C \): - The sum of the roots \( \alpha + \beta \) is given by: \[ -\frac{B}{A} = -\frac{2k + 1}{3} \] - The product of the roots \( \alpha \beta \) is given by: \[ \frac{C}{A} = \frac{-k - 5}{3} \] ### Step 3: Set up the equation based on the problem statement According to the problem, the sum of the roots is half of the product of the roots: \[ -\frac{2k + 1}{3} = \frac{1}{2} \cdot \frac{-k - 5}{3} \] ### Step 4: Eliminate the denominators To eliminate the denominators, we can multiply both sides by \( 6 \) (the least common multiple of 3 and 2): \[ 6 \left(-\frac{2k + 1}{3}\right) = 6 \left(\frac{1}{2} \cdot \frac{-k - 5}{3}\right) \] This simplifies to: \[ -2(2k + 1) = -k - 5 \] ### Step 5: Expand and simplify the equation Expanding the left side: \[ -4k - 2 = -k - 5 \] ### Step 6: Rearrange the equation to solve for \( k \) Bringing all terms involving \( k \) to one side and constant terms to the other side: \[ -4k + k = -5 + 2 \] This simplifies to: \[ -3k = -3 \] ### Step 7: Solve for \( k \) Dividing both sides by -3: \[ k = 1 \] ### Final Answer Thus, the value of \( k \) is: \[ \boxed{1} \]
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