I'm having trouble with these types of questions. I have the following vector $u = (4, 7, -9)$ and it wants me to find 2 vectors that are perpendicular to this one.
I know that $(4,7,-9)\cdot (x,y,z) = 0$.
The dot product of two vectors must equal to zero in order for them to be perpendicular.
But that doesn't tell me much at this point. Any inputs?