Answer:
A) 
B) T = -5 °C
Step-by-step explanation:
A) Let T be the change in temperature of the week. T is determined as the total temperature change (-20°C) divided by the number of weeks that have passed (4 weeks). The expression is:

B) In order to simplify the expression, simply perform the division.

This means that the temperature has dropped by 5 degrees each week.
Dy/dx = dy/dt / dx/dt
dy/dx = 12x^2 + 4
when x = 2 , dydx = 52
52 = dy/dt / 3
so dy/dt = 156 (answer)
Can't see the graph can you make it more clear?
You didn't give the multiple choice so no one can help you do make sure to include that next time