Respuesta :

Given the function:

[tex]f(x)=3x[/tex]

• You need to substitute this value of "x" into the function:

[tex]x=-4[/tex]

And then evaluate, in order to find:

[tex]f(-4)[/tex]

You get:

[tex]f(-4)=3(-4)[/tex][tex]f(-4)=-12[/tex]

Remember the Sign Rules for Multiplication:

[tex]\begin{gathered} +\cdot+=+ \\ -\cdot-=+ \\ -\cdot+=- \\ +\cdot-=- \end{gathered}[/tex]

• Substitute this value of "x" into the function:

[tex]x=3[/tex]

Then:

[tex]f(3)=3(3)[/tex]

Evaluate, in order to find:

[tex]f(3)[/tex]

You get:

[tex]f(3)=9[/tex]

Hence, the answer is:

[tex]\begin{gathered} f(-4)=-12 \\ f(3)=9 \end{gathered}[/tex]