WBJEE · Maths · Straight Lines
Let each of the equations \(x^{2}+2 x y+a y^{2}=0 \& a x^{2}+2 x y+y^{2}=0\) represent two straight lines passing through the origin. If they have a common line, then the other two lines are given by
- A \(x-y=0, x-3 y=0\)
- B \(x+3 y=0,3 x+y=0\)
- C \(3 x+y=0,3 x-y=0\)
- D \((3 x-2 y)=0, x+y=0\)
Answer & Solution
Correct Answer
(B) \(x+3 y=0,3 x+y=0\)
Step-by-step Solution
Detailed explanation
Hint: \(\left(\frac{\mathrm{x}}{\mathrm{y}}\right)^{2}+2\left(\frac{\mathrm{x}}{\mathrm{y}}\right)+\mathrm{a}=0 \& \mathrm{a}\left(\frac{\mathrm{x}}{\mathrm{y}}\right)^{2}+2\left(\frac{\mathrm{x}}{\mathrm{y}}\right)+1=0\) have exactly one root in common (taking…
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