3.64 is the estimated difference
Substituting the data points into the model:
f(x)= -x2 + 2x -3
f(-2)=-11
f(0)=-3
f(1)=-2
f(3)=-6
f(5)=-18
So A is the right ans.
Answer:

Step-by-step explanation:
Call 
Now, 

This is the inverse of the given function.
You can cross - verify it by substituting a point, say, 
We see that the point satisfies both the equations.
52.4/2= 26.2
26.2-3= 23.2
So the original number = 23.2
Hi
Left to do 40% of the shopping
12 items ⇒ 60% of the items
x items ⇒ 40% of the items
60x = 12(40)
60x = 480
x = 480/60
x = 48/6
x = 8 items
Answer:
Left 8 items of the list (40% of the shopping)
Items: 12+8 = 20 items on her list