Let a =2 i +7 j - k , b =3 i +5 k and c = i - j +2 k . Let d be a vector which is perpendicular to both a and...

Question

Let a =2 i +7 j - k , b =3 i +5 k and c = i - j +2 k . Let d be a vector which is perpendicular to both a and b , and c . d =12. Then (- i + j - k ).( c d ) is equal to -

Accepted Answer

(B)

JEE Main 2023 Mathematics question

Solution