Basically f(x)=5x means whatever number you plug in will be your x coordinate, and the result will be your y coordinate.
(1,5) (2,10) (3,15) (4,20) and so on. 1,2,3 and 4 are x coordinates plugged into the equation, the y coordinate is whatever 1,2,3 and 4 multiplied by 5 is.
i do not understand what you are asking help for?
The leading term is 18, since the term on the right can be simplifies to 18(2x+1)(2-2x). 18 is the first term in the sequence.
Daniela made her error on step 3 because it says:
"Find the ratio of the differences of the means compared to the mean absolute deviation.
She didn't find the difference between the today and last week means. She just put the mean as a whole.
