Let a =6 i +9 j +12 k , b = i +11 j -2 k and c be vectors such that a c = a b . If a . c =-12, c .( i -2 j +...

Question

Let a =6 i +9 j +12 k , b = i +11 j -2 k and c be vectors such that a c = a b . If a . c =-12, c .( i -2 j + k )=5, then c .( i + j + k ) is equal to ______.

Accepted Answer

11

JEE Main 2023 Mathematics question

Solution