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Three Dimensional Geometry

Question
CBSEENMA12033518

Find the equation of the plane containing the line
fraction numerator straight x plus 2 over denominator 2 end fraction space equals space fraction numerator straight y plus 3 over denominator 3 end fraction space equals fraction numerator straight z minus 4 over denominator negative 2 end fraction
and the point (0, 6, 0).

Solution
The equations of line are
fraction numerator straight x plus 2 over denominator 2 end fraction space equals space fraction numerator straight y plus 3 over denominator 3 end fraction space equals fraction numerator straight z minus 4 over denominator negative 2 end fraction                                ...(1)
It passes through (-2, -3, 4) and has direction-ratios 2, 3, –2.
Since the plane contains line (1)
∴  equation of plane is
a(x + 2) + b(y + 3) + c(z – 4) = 0    ...(2)
where 2a + 3b – 2c = 0    ...(3)
Again plane (2) passes through (0, 6, 0)
∴  a (0 + 2) + b (6 + 3) + c (0 – 4) = 0
or 2 a + 9 b – 4c = 0    ...(4)
Solving (3) and (4), we get,
                          fraction numerator straight a over denominator negative 12 plus 18 end fraction space equals space fraction numerator straight b over denominator negative 4 plus 8 end fraction space equals space fraction numerator straight c over denominator 18 minus 6 end fraction
therefore space space space space space space space space space space space straight a over 6 equals space straight b over 4 space equals straight c over 12 space space space space space space space space or space space space space straight a over 3 equals straight b over 2 space equals space straight c over 6 space equals space straight k space left parenthesis say right parenthesis
∴   a = 3 k, b = 2 k, c = 6 k
Putting these values of a, b. c in (2), we get,
3 k (x + 2) + 2 k (y + 3) + 6 k (z – 4) = 0
or 3 (x + 2) + 2 (y + 3) + 6 (z – 4) = 0
or  3x + 6 + 2y + 6 + 6 z –24 = 0
or 3 x + 2 y + 6 z – 12 = 0