Math Help - linear dependence

1. linear dependence

Find values of t for which the set of vectors
2 2t+6
-t 4t

is linearly dependent.

2. they are linearly dependent ,is equavalent to say:
$2\times 4t=-t\times (2t+6)$

Find values of t for which the set of vectors
2 2t+6
-t 4t

is linearly dependent.