LinAlg - a few questions?

so i have the matrices

[-12

16

-13] = A

(it is a 3x1 matrix)

[-3

5

-4] = B

[-3

3

-3] = C

Determine whether A, B, and C are linearly independent

If they are linearly dependent, determine a non-trivial linear relation - (a non-trivial relation is three numbers which are not all three zero.) otherwise, if the vectors are linearly independent, enter 0's for the coefficients, since that relationship **always **holds.

______A + ______B + _______C = 0

my teacher told me to do something with C1, C2... Cn... but I have no idea what that means! haha

thanks so much in advance :)