The value of $\lambda$, for which the lines $3 x-4 y=13,8 x-11 y=33$ and $2 x-3 y+\lambda=0$ are concurrent is

The value of $\lambda$, for which the lines $3 x-4 y=13,8 x-11 y=33$ and $2 x-3 y+\lambda=0$ are concurrent is
  1. -1
  2. -7
  3. $\frac{1}{7}$
  4. 9

Solution

For concurrency of 3 lines the determinant of coefficients of equations should be 0 . i.e. $\left|\begin{array}{ccc}3 & -4 & -13 \\ 8 & -11 & -33 \\ 2 & -3 & \lambda\end{array}\right|=0$ $\Rightarrow 3(-11 \lambda-99)+4(8 \lambda+66)-13(-24+22)=0$ $\Rightarrow-33 \lambda-297+32 \lambda+264+312-286=0$ $\Rightarrow-\lambda-583+576=0 \Rightarrow \lambda=-7$

Asked in: TEST SERIES MHT-CET Full Test 6

Practice more Straight Lines questions on Aicharya