Find k for the given plane x + 2y + kz + 2 = 0 and directional ratios of a line (8, 3, 2), if they are parallel to each other.

Category: QuestionsFind k for the given plane x + 2y + kz + 2 = 0 and directional ratios of a line (8, 3, 2), if they are parallel to each other.
Editor">Editor Staff asked 11 months ago

Find k for the given plane x + 2y + kz + 2 = 0 and directional ratios of a line (8, 3, 2), if they are parallel to each other.
 
(a) 21
 
(b) -17
 
(c) 12
 
(d) -7
 
This question was addressed to me in homework.
 
My question is from Three Dimensional Geometry in portion Three Dimensional Geometry of Mathematics – Class 12
NCERT Solutions for Subject Clas 12 Math Select the correct answer from above options 
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1 Answers
Editor">Editor Staff answered 11 months ago

The correct answer is (d) -7
 
For explanation: The condition for a plane and a line are parallel to each other is a1a + b1b + c1c = 0.
 
8(1) + 3(2) + 2(k) = 0
 
2(k) = -14
 
k = -7