Answer:
A function is a relation in which each input has only one output. In the relation , y is a function of x, because for each input x (1, 2, 3, or 0), there is only one output y. x is not a function of y, because the input y = 3 has multiple outputs: x = 1 and x = 2.
I hope it's helpful!
Let's say hmm let's use the figures in thousands, so
model A costs 90 + 4 per year, so... ok.. after "t" years, then the cost for model A is then 90 + 4*t, or
A = 90 + 4t.
now, model B is 70 + 10 per year, so,... after "t" years, model B is then
B = 70 + 10 * t, or
B = 70 + 10t.
if we were to assume A < B, namely the cost of A is less than B, what would the years be? namely, what's "t"?

after that period, then A becomes cheaper than B.
It appears that you have here a list of the # of minutes spent each day on HW, and that y ou need to sum up this list to answer the question. Unfortunately I cannot read the last numeral.
The answer (assuming that my guess is correct) would be found as follows:
Total hours spent on HW in one week = (18+20+22+11+19+18+ ?? )