### Video Transcript

If π of π₯ equals five plus three
π₯, which of the following is equivalent to π of negative three π₯?

Weβre starting out with π of π₯
equals five plus three π₯. And we need to plug in negative
three π₯ for the π₯-value. This means that anywhere in our
function where π₯ shows up we need to replace it with negative three π₯. After we do that, we can simplify
the second function, bring down the five. We can multiply three by negative
three, which gives negative nine and thatβs been multiplied by π₯.

We could also think of it another
way. We could think of it as multiplying
the π₯ thatβs there by negative three. And in that case, every place we
see π₯, we would need to multiply that π₯ by negative three. The expression would then be three
times negative three times π₯. And that simplifies to negative
nine π₯.

The only answer choice that
reflects this expression is c five minus nine π₯.