Given the function :
[tex]f(x)=-x-11[/tex]we need to find the value of 3f(5) x f(2)
so, to find the value of f(5), substitute with x = 5 at the given function
And to find the value of f(2) , substitute with x = 2 at the given function
so,
[tex]\begin{gathered} f(5)=-5-11=-16 \\ \\ f(2)=-2-11=-13 \\ \\ 3f(5)\cdot f(2)=3\cdot-16\cdot-13=624 \end{gathered}[/tex]