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AP EAMCET · Maths · Pair of Lines

If \(a x^2+2 h x y-2 a y^2+3 x+15 y-9=0\) represents a pair of lines intersecting at \((1,1)\), then ah \(=\)

  1. A 14
  2. B -15
  3. C -7
  4. D 9
Verified Solution

Answer & Solution

Correct Answer

(C) -7

Step-by-step Solution

Detailed explanation

\(A = a, H = h, B = -2a, G = 3/2, F = 15/2\) \(Ax + Hy + G = 0 \Rightarrow a(1) + h(1) + 3/2 = 0 \Rightarrow a + h = -3/2\) \(Hx + By + F = 0 \Rightarrow h(1) + (-2a)(1) + 15/2 = 0 \Rightarrow h - 2a = -15/2\) \((a+h) - (h-2a) = -3/2 - (-15/2)\)…