Answer:
+$90;
$1,600
Explanation:
The equation,
, given to us tells us much about the situation described above.
y = total pay
x = number of copies of Math is fun
1600 = y-intercept, that is the starting value or the pay he gets only if Sam sold 0 copy of Math is fun. That is, when x = 0, y = 1,600.
90 = unit rate or the change in the total pay for each copy of Math is fun that Sam sells.
Therefore, our answers would be:
+$90, and $1,600