Answer
$f(-x) = 3x+4$
Work Step by Step
To find the value of $f(-x)$, substitute $-x$ to $x$ in $f(x)$ to obtain:
$f(x)=-3x+4
\\f(-x)=-3(-x)+4
\\f(-x) = 3x+4$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.