# Math Help - Algebra Homework help

1. ## Algebra Homework help

I'm working on a worksheet assigned in class, and I'm completely stumped about one problem.

My teacher never went over anything like this, and there's no a single example in my entire book of how to do this problem.

So now this is my last resort. I've uploaded an image of the problem, and I hope someone can help.

The problems with just "Find F(5)" on the graph are really simple. However, I've never seen or dealt with one like this and I don't even know where to start.

2. $f(5)$

$x=5$, look at the graph and you'll see that $y=-2\,\therefore\,f(5)=-2$

Well, to get the desired, follow the same method, not hard.

3. I understand that, but again, the problem there is different.

What do I do when they throw in addition and multiplication to the same problem?

I already have a million examples of F(5). I have no examples of the problem I'm shown.

I'm just not seeing it.

4. So, what's the matter?

Just look at $f(4)$ and $f(1)$, when you get them, just set $f(4)+3\cdot f(1)$

It's simple, there's nothing to worry about.

5. I'm still confused...

How do you add points on a graph?

Okay, this is what I get.

f(4) = 1
f(1) = -2

How do I plug this in? What does the three have to do with anything?

Would it just be 1 * 3(-2)?

6. $f(4)+3\cdot f(1)=1+3\cdot(-2)=1-6=-5$

7. Ah, I see. I wasn't thinking that's how it worked. Thanks.