Question

Find f(-4) and f(3) for the following funxripnf(x)=3x

Answer 1

Given the function:

`f(x)=3x`

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

`x=-4`

And then evaluate, in order to find:

`f(-4)`

You get:

`f(-4)=3(-4)`
`f(-4)=-12`

Remember the Sign Rules for Multiplication:

`\begin{gathered} +\cdot+=+ \\ -\cdot-=+ \\ -\cdot+=- \\ +\cdot-=- \end{gathered}`

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

`x=3`

Then:

`f(3)=3(3)`

Evaluate, in order to find:

`f(3)`

You get:

`f(3)=9`

Hence, the answer is:

`\begin{gathered} f(-4)=-12 \\ f(3)=9 \end{gathered}`