If the lines $4 x+3 y-1=0, x-y+5=0$ and $k x+5 y-3=0$ are concurrent, then $k=$
If the lines $4 x+3 y-1=0, x-y+5=0$ and $k x+5 y-3=0$ are concurrent, then $k=$
- 5
- 6
- 7
- 4
Solution
For concurrency $\left|\begin{array}{ccc}4 & 3 & -1 \\ 1 & -1 & 5 \\ k & 5 & -3\end{array}\right|=0$
$\Rightarrow 4(3-25)+3(5 k+3)-1(5+k)=0$
$\Rightarrow-88+15 k+9-5-k=0$
$\Rightarrow-84+14 k=0$
$\Rightarrow k=6$
Asked in: MHT CET 2022 (07 Aug Shift 2)
Practice more Straight Lines questions on Aicharya