Answer
The value of \[f\left( -4 \right)\]is \[-64\].
Work Step by Step
The provided equation is\[y=-3{{x}^{2}}+6x+8\].
To find the value of \[f\left( -4 \right)\], substitute the value \[x=-4\] in the provided equation.
\[\begin{align}
& y=-3{{\left( -4 \right)}^{2}}+6\left( -4 \right)+8 \\
& =-48-24+8 \\
& =-64
\end{align}\]
