Help me!

First, we need to simplify the equation, so let's combine all the like terms. 

We get $-15x^2-kx+45$

Now, in order for the solutions to be nonreal, the descriminant must be less than 0.

The descriminant is $b^2-4ac$, so plugging in our values, we get

$(-15)^2 - 4(-k)(45) < 0 \\ 225+180k<0\\ k<-1.25$

Therefore, the biggest interger k can be is -2. 

So -2 is our answer!

Thanks! :)