If the lines \(3 x+y-2=0, p x+2 y-3=0\) and \(2 x-y-3=0\) are concurrent, then \(p=\)

If the lines \(3 x+y-2=0, p x+2 y-3=0\) and \(2 x-y-3=0\) are concurrent, then \(p=\)
  1. -5
  2. 5
  3. 3
  4. -3

Solution

It is given that lines \(3 x+y-2=0, p x+2 y-3=0\) and \(2 x-y-3=0\) are concurrent, so \(\begin{array}{lll} \left|\begin{array}{rrr} 3 & 1 & -2 \\ p & 2 & -3 \\ 2 & -1 & -3 \end{array}\right|=0 \\ \Rightarrow 3(-6-3)-1(-3 p+6)-2(-p-4)=0 \\ \Rightarrow -27+3 p-6+2 p+8=0 \\ \Rightarrow 5 p-25=0 \Rightarrow p=5 \end{array}\) Hence, option (b) is correct.

Asked in: AP EAMCET 2020 (21 Sep Shift 1)

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