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The system of equations: x+ky+3z=0, 3x...

The system of equations:
`x+ky+3z=0`, `3x+ky-2z=0`, `2x+3y-4z=0` has non- trivial solution. when `k=`

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To find the value of \( k \) for which the system of equations has a non-trivial solution, we need to analyze the determinant of the coefficient matrix. The system of equations is given as: 1. \( x + ky + 3z = 0 \) 2. \( 3x + ky - 2z = 0 \) 3. \( 2x + 3y - 4z = 0 \) ### Step 1: Form the Coefficient Matrix The coefficient matrix \( A \) can be formed from the coefficients of \( x \), \( y \), and \( z \) in the equations: \[ A = \begin{bmatrix} 1 & k & 3 \\ 3 & k & -2 \\ 2 & 3 & -4 \end{bmatrix} \] ### Step 2: Calculate the Determinant of the Coefficient Matrix To find the value of \( k \) for which there is a non-trivial solution, we need to set the determinant of matrix \( A \) equal to zero: \[ \text{det}(A) = \begin{vmatrix} 1 & k & 3 \\ 3 & k & -2 \\ 2 & 3 & -4 \end{vmatrix} \] ### Step 3: Expand the Determinant Using the formula for the determinant of a \( 3 \times 3 \) matrix: \[ \text{det}(A) = 1 \cdot \begin{vmatrix} k & -2 \\ 3 & -4 \end{vmatrix} - k \cdot \begin{vmatrix} 3 & -2 \\ 2 & -4 \end{vmatrix} + 3 \cdot \begin{vmatrix} 3 & k \\ 2 & 3 \end{vmatrix} \] Calculating each of these \( 2 \times 2 \) determinants: 1. \( \begin{vmatrix} k & -2 \\ 3 & -4 \end{vmatrix} = k(-4) - (-2)(3) = -4k + 6 \) 2. \( \begin{vmatrix} 3 & -2 \\ 2 & -4 \end{vmatrix} = 3(-4) - (-2)(2) = -12 + 4 = -8 \) 3. \( \begin{vmatrix} 3 & k \\ 2 & 3 \end{vmatrix} = 3(3) - k(2) = 9 - 2k \) Putting it all together: \[ \text{det}(A) = 1(-4k + 6) - k(-8) + 3(9 - 2k) \] \[ = -4k + 6 + 8k + 27 - 6k \] \[ = (-4k + 8k - 6k) + (6 + 27) \] \[ = -2k + 33 \] ### Step 4: Set the Determinant to Zero For a non-trivial solution, we set the determinant equal to zero: \[ -2k + 33 = 0 \] ### Step 5: Solve for \( k \) Rearranging the equation gives: \[ -2k = -33 \] \[ k = \frac{33}{2} \] ### Final Answer Thus, the value of \( k \) for which the system of equations has a non-trivial solution is: \[ \boxed{\frac{33}{2}} \]
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