Question 1208026
{{{f(-1)=12}}} means that the point  (-1,12) is a point on the function f.


Use that known point for x and f(x).

{{{12=3(-1)^2-B(-1)+4}}}

{{{3+B+4=12}}}

{{{B+7=12}}}

{{{highlight(B=5)}}}----------and could have been done in one or two fewer steps.