A picture of the problem is here: https://gyazo.com/7b4dd032fbb0cff5f5f528bb0928987f
I'm confused on how to do this, the answer needs to be an exact number. My friend ran me through how to do the first one but I'm still very confused on the method.
Another type of problem I'm very confused on is here: https://gyazo.com/7d63795b0dee0a3a35fed4980cc0d6ba
If anyone could be kind enough, please let me know the method to solve these as I don't know.
Thanks a lot!
The graph of $f$ is all the points $(x, y)$ where $y = f(x)$. So to find the value of $f(-1)$, look for $-1$ on the $x$-axis. Follow it straight up (or down for some functions, but not for this one) until you arrive at the graph of $f$. Then head across horizontally until you get to the $y$-axis to find the value of $y = f(-1)$. That tells you what $f(-1)$ is. Do the same thing for $g(-1)$.
Then $$(f + g)(-1) = f(-1) + g(-1)$$ $$(f - g)(-1) = f(-1) - g(-1)$$ $$(fg)(-1) = f(-1) \cdot g(-1)$$ $$\left (\frac f g \right)(-1) = \frac{f(-1)}{g(-1)}$$
For the 2nd problem, $(g \circ f)(0) = g( f(0))$ So find $f(0)$ as above. Whatever that value is, find the value of $g(x)$ when $x = f(0)$. That is your answer.