Question
Question: If the planes \(3x - 2y + 2z + 17 = 0\)and \(4x + 3y - kz = 25\) are mutually perpendicular , then \...
If the planes 3x−2y+2z+17=0and 4x+3y−kz=25 are mutually perpendicular , then k=
A
3
B
– 3
C
9
D
– 6
Answer
3
Explanation
Solution
Obviously, 3×4+(−2)×3+2×(−k)=0
⇒12−6−2k=0⇒k=3