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The set of real values of k for which th...

The set of real values of k for which the lines `x + 3y +1=0, kx + 2y-2=0` and `2x-y + 3 = 0` form a triangle is

A

`R-{-4,(2)/(3)}`

B

`R-{-4,(-6)/(5),(2)/(3)}`

C

`R-{(-2)/(3),4}`

D

R

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To determine the set of real values of \( k \) for which the lines \( x + 3y + 1 = 0 \), \( kx + 2y - 2 = 0 \), and \( 2x - y + 3 = 0 \) form a triangle, we need to ensure that the lines are not parallel and not concurrent. ### Step 1: Find the slopes of the lines 1. **First line**: \( x + 3y + 1 = 0 \) - Rearranging gives \( 3y = -x - 1 \) or \( y = -\frac{1}{3}x - \frac{1}{3} \) - **Slope**: \( m_1 = -\frac{1}{3} \) 2. **Second line**: \( kx + 2y - 2 = 0 \) - Rearranging gives \( 2y = -kx + 2 \) or \( y = -\frac{k}{2}x + 1 \) - **Slope**: \( m_2 = -\frac{k}{2} \) 3. **Third line**: \( 2x - y + 3 = 0 \) - Rearranging gives \( y = 2x + 3 \) - **Slope**: \( m_3 = 2 \) ### Step 2: Ensure the lines are not parallel For the lines to form a triangle, they must not be parallel. This means their slopes must be different. 1. **Condition 1**: \( m_1 \) and \( m_2 \) should not be equal: \[ -\frac{k}{2} \neq -\frac{1}{3} \] This simplifies to: \[ k \neq \frac{2}{3} \] 2. **Condition 2**: \( m_2 \) and \( m_3 \) should not be equal: \[ -\frac{k}{2} \neq 2 \] This simplifies to: \[ k \neq -4 \] ### Step 3: Ensure the lines are not concurrent The lines are concurrent if the determinant of the coefficients of \( x \), \( y \), and the constant terms is zero. We form the matrix: \[ \begin{vmatrix} 1 & 3 & -1 \\ k & 2 & 2 \\ 2 & -1 & -3 \end{vmatrix} \] Calculating the determinant: \[ = 1 \cdot (2 \cdot (-3) - 2 \cdot (-1)) - 3 \cdot (k \cdot (-3) - 2 \cdot 2) - 1 \cdot (k \cdot (-1) - 2 \cdot 2) \] \[ = 1 \cdot (-6 + 2) - 3 \cdot (-3k - 4) - 1 \cdot (-k - 4) \] \[ = -4 + 9k + 12 + k + 4 \] \[ = 10k + 12 \] Setting the determinant not equal to zero for non-concurrency: \[ 10k + 12 \neq 0 \] \[ 10k \neq -12 \quad \Rightarrow \quad k \neq -\frac{6}{5} \] ### Step 4: Combine conditions The values of \( k \) for which the lines form a triangle are: 1. \( k \neq \frac{2}{3} \) 2. \( k \neq -4 \) 3. \( k \neq -\frac{6}{5} \) ### Final Answer The set of real values of \( k \) for which the lines form a triangle is: \[ k \in \mathbb{R} \setminus \left\{ \frac{2}{3}, -4, -\frac{6}{5} \right\} \]

To determine the set of real values of \( k \) for which the lines \( x + 3y + 1 = 0 \), \( kx + 2y - 2 = 0 \), and \( 2x - y + 3 = 0 \) form a triangle, we need to ensure that the lines are not parallel and not concurrent. ### Step 1: Find the slopes of the lines 1. **First line**: \( x + 3y + 1 = 0 \) - Rearranging gives \( 3y = -x - 1 \) or \( y = -\frac{1}{3}x - \frac{1}{3} \) - **Slope**: \( m_1 = -\frac{1}{3} \) 2. **Second line**: \( kx + 2y - 2 = 0 \) ...
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