Mathematics - Straight Lines Question with Solution | TestHub

MathematicsStraight LinesPair of St. linesMedium2 minQB

MathematicsMediumsingle choice

$9 x^{2} + 2 h x y + 4 y^{2} + 6 x + 2 f y - 3 = 0$ represents two parallel lines then

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Solution:

Since the given equation represents a pair of parallel lines, we have $h^{2} = ab \Rightarrow h = \pm 6$ . Condition for pair of lines: determinant with Row 1: 9, h, 3; Row 2: h, 4, f; Row 3: 3, f, -3 equals 0 $\Rightarrow 108 \pm 36 f - 9 f^{2} - 144 = 0 \Rightarrow f = 2$ \& $h = 6 \Rightarrow f = - 2, h = - 6$ .

Stream:JEESubject:MathematicsTopic:Straight LinesSubtopic:Pair of St. lines

⏱ 2mℹ️ Source: QB

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