Y= -2+21
This is because the slope needs to be the negative reciprocal of 1/2 so the slope is -2 then you take the point (5,11) and plug that an the -2 into y=m(x)+b and you solve for b. In the end you get 21
Both can be right because if the function goes up, turns and goes down, between x = -2 and x = 2, it can happen that f(-2) = f(2) and then the average rate of change is [f(2) - f(-2)] / [2-(-2)] which is 0/4 = 0.
Degree 4 means you'll have x^4 as your leading term. Multiplicity of 3 means you have the same factor 3 times. So if x = -2, then (x + 2) = 0, so (x + 2) is used 3 times. FOIL that out 3 times and you get x^3 + 6x^2 + 12x + 8. Now multiply by (x + 0) to get a 4th degree polynomial of x^4 + 6x^3 + 12x^2 + 8x. There!