# Math Help - Perpendicular vectors

1. ## Perpendicular vectors

I've have another question

how do you find a vector which is perpendicular to both 3i-6j-4k and -3i+2j+2k

2. Originally Posted by kandyfloss
how do you find a vector which is perpendicular to both 3i-6j-4k and -3i+2j+2k
Find the cross-product: $<3,-6,-4>\times<-3,2,2>$.

3. i need to find without using the cross product,since we haven't learnt that yet