Answer
See below
Work Step by Step
Given: $f(x)=-6x^2$
Since the vertex form is $y=a(x-h)^2+k$, we know: $a=-6\\h=0\\k=0$
The vertex then will be $(h,k)=(0,0)$
Find some values: $x=1 \rightarrow y=-6\\x=2 \rightarrow y=-24\\x=3 \rightarrow y=-54$