If one of the lines \(2 x^2-x y+b y^2=0\) passes through the point \((-4,-2)\), then \(b^2=\)

If one of the lines \(2 x^2-x y+b y^2=0\) passes through the point \((-4,-2)\), then \(b^2=\)
  1. -6
  2. 36
  3. 4
  4. 16

Solution

It is given that one of the lines \(2 x^2-x y+b y^2=0\) passes through the point \((-4,-2)\), so \(\begin{aligned} & 2(-4)^2-(-4)(-2)+b(-2)^2 =0 \\ \Rightarrow & 32-8+4 b=0 \Rightarrow b =-6 \\ \therefore & b^2= 36 \end{aligned}\) Hence, option (b) is correct.

Asked in: AP EAMCET 2020 (21 Sep Shift 2)

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