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If the lines 3x^(2)-4xy +y^(2) +8x - 2y-...

If the lines `3x^(2)-4xy +y^(2) +8x - 2y- 3 = 0` and `2x - 3y +lambda = 0` are concurrent, then the value of `lambda` is

A

`4pi - 11`

B

`-11`

C

`(1)/(11)`

D

11

Text Solution

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To solve the problem, we need to find the value of \( \lambda \) such that the lines represented by the equations \( 3x^2 - 4xy + y^2 + 8x - 2y - 3 = 0 \) and \( 2x - 3y + \lambda = 0 \) are concurrent. ### Step 1: Differentiate the first equation with respect to \( x \) We start with the equation of the pair of straight lines: \[ 3x^2 - 4xy + y^2 + 8x - 2y - 3 = 0 \] Differentiating with respect to \( x \) while treating \( y \) as a constant gives: \[ \frac{d}{dx}(3x^2) - \frac{d}{dx}(4xy) + \frac{d}{dx}(y^2) + \frac{d}{dx}(8x) - \frac{d}{dx}(2y) - \frac{d}{dx}(3) = 0 \] This simplifies to: \[ 6x - 4y + 8 = 0 \] ### Step 2: Differentiate the first equation with respect to \( y \) Next, we differentiate the same equation with respect to \( y \) while treating \( x \) as a constant: \[ \frac{d}{dy}(3x^2) - \frac{d}{dy}(4xy) + \frac{d}{dy}(y^2) + \frac{d}{dy}(8x) - \frac{d}{dy}(2y) - \frac{d}{dy}(3) = 0 \] This simplifies to: \[ -4x + 2y - 2 = 0 \] ### Step 3: Solve the two equations Now we have two equations: 1. \( 6x - 4y + 8 = 0 \) (Equation 1) 2. \( -4x + 2y - 2 = 0 \) (Equation 2) From Equation 1, we can express \( x \) in terms of \( y \): \[ 6x = 4y - 8 \] \[ x = \frac{4y - 8}{6} = \frac{2y - 4}{3} \] Substituting this expression for \( x \) into Equation 2: \[ -4\left(\frac{2y - 4}{3}\right) + 2y - 2 = 0 \] Multiplying through by 3 to eliminate the fraction: \[ -4(2y - 4) + 6y - 6 = 0 \] \[ -8y + 16 + 6y - 6 = 0 \] Combining like terms: \[ -2y + 10 = 0 \] Thus, we find: \[ 2y = 10 \] \[ y = 5 \] ### Step 4: Substitute \( y \) back to find \( x \) Now substituting \( y = 5 \) back into the expression for \( x \): \[ x = \frac{2(5) - 4}{3} = \frac{10 - 4}{3} = \frac{6}{3} = 2 \] ### Step 5: Substitute \( x \) and \( y \) into the second line equation Now we have \( x = 2 \) and \( y = 5 \). We substitute these values into the second line equation: \[ 2x - 3y + \lambda = 0 \] Substituting \( x \) and \( y \): \[ 2(2) - 3(5) + \lambda = 0 \] \[ 4 - 15 + \lambda = 0 \] \[ \lambda - 11 = 0 \] Thus, we find: \[ \lambda = 11 \] ### Final Answer The value of \( \lambda \) is \( 11 \). ---

To solve the problem, we need to find the value of \( \lambda \) such that the lines represented by the equations \( 3x^2 - 4xy + y^2 + 8x - 2y - 3 = 0 \) and \( 2x - 3y + \lambda = 0 \) are concurrent. ### Step 1: Differentiate the first equation with respect to \( x \) We start with the equation of the pair of straight lines: \[ 3x^2 - 4xy + y^2 + 8x - 2y - 3 = 0 \] Differentiating with respect to \( x \) while treating \( y \) as a constant gives: \[ \frac{d}{dx}(3x^2) - \frac{d}{dx}(4xy) + \frac{d}{dx}(y^2) + \frac{d}{dx}(8x) - \frac{d}{dx}(2y) - \frac{d}{dx}(3) = 0 \] ...
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