Let

= a column vector with 1, 4, -2;

= a column vector with -2, -3, 7; and

= a column vector with entries 4, 1, h.
(I hope this is an adequate description. I forgot how to write pretty matrices in tex ^_^;)
For what values of h is

in the plane spanned by

and

?
I turned this into an augmented matrix but had trouble reducing it to RREF.