-6(-3)=18, so that is true
-6+(-3)=-6-3=-9 so that is true
-6-(-3)=-6+3=-3 FALSE
-6 ÷ (-2)=2 so that is true
Answer is C
Answer:

Step-by-step explanation:
Let n = number of notebooks
and f = number of fodders
You have a system of two equations:


Jenna bought
.
Check:

OK.
The given graph is a downward parabola.
The roots of the equation is -2 and -8, and the vertex is (-5,7).
The general root form of parabola will be,
a(x-(-2))(x-(-8))=a(x+2)(x+8).
The value of a can be determined from the coordinate of vertex,

Thus, the required quadratic is,

The value of f(-6) can be determined as,

Thus, the requried value of f(-6) is 6.22.