Let the abscissae of two points P and Q on a circle be the roots of x2 – 4x – 6 = 0 and the ordinates of P and Q be the roots of y2 + 2y – 7 = 0. If PQ is a diameter of the circle x2 + y2 + 2ax + 2by + c = 0, then the value of (a + b +) is……………
Let the abscissae of two points P and Q on a circle be the roots of x2 – 4x – 6 = 0 and the ordinates of P and Q be the roots of y2 + 2y – 7 = 0. If PQ is a diameter of the circle x2 + y2 + 2ax + 2by + c = 0, then the value of (a + b +) is……………
Option 1 -
12
Option 2 -
13
Option 3 -
14
Option 4 -
16
Asked by Shiksha User
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1 Answer
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Correct Option - 1
Detailed Solution:Abscissae of PQ are roots of x2 – 4x – 6 = 0
Ordinates of PQ are roots of y2 + 2y – 7 = 0 and PQ is diameter
Equation of circle is
But, given
By comparison a = -2, b = 1, c = -13 Þ a + b – c = -2 + 1 + 13 = 12
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