General Idea:
If the function is of the form f(x) = mx + b, then m represent the slope and b represent the y-intercept.
Applying the concept:
[tex] f(x)=4.99x+5.75 [/tex]
Where:
[tex] x \;\; \; \; \; \; \rightarrow \; Number \; of\; Pounds\; of\; Shipping\; Package\\ \\ f(x) \; \rightarrow \; Total\; Cost [/tex]
To find the fixed fee, we need to substitute 0 for x, because fixed fee is the fixed cost when there is NO package is shipped.
[tex] f(0) = 4.99(0)+5.75\\ \\ Fixed \; Cost \; = \; \$\; 5.75 [/tex]