Q89 / 160 · TS EAMCET 2022 (18 Jul Shift 1) · Mathematics

The equation x2-y2+ax+b=0 represents a pair of lines for the ordered pair a,b=

  • A
    2,6
  • B
    3,4
  • C
    4,8
  • Correct answer
    D
    6,9

Solution

Given,

x2-y2+ax+b=0 represents pair of straight line

We know that if ax2+2hxy+by2+2gx+2fy+c=0 represent a pair of straight line then △=2fgh+abc-af2-bg2-ch2=0

So, on comparing with given equation we get,

△=0+1×-1×b-0+1a22=0

⇒a2-4b=0

So, only 6,9 will satisfy the given equation.

Hence, the correct answer is option: 'D'.

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