Answer:
2. variable 3. variable 4. constant
Step-by-step explanation:
There are two ways of thinking about it: logically and mathematically.
Logically, a company is very unlikely to sell the exact same number of computers each week, so you'd expect it to vary. Mathematically, if you calculate two slopes using 4 points from the same table, like (12-6)/(4-2) and (60-25)/(20-11), they aren't always equal (those expressions are not equal to each other), so it varies.
Logically, objects accelerate as they fall, so their speed (rate of change) will increase. Mathematically, do the same as above and see that (64-16)/(2-1) is way smaller than (256-144)/(4-3), so it varies.
Logically, you'd expect each sweater to cost the exact same every time, so you'd expect it to be constant. Mathematically, do the same as above and see that the slope is constantly $19 per sweater.
Let me know if you need more specificity or steps! (:
