Answer:
8 trust me brainliest and 5 star pls......
Step-by-step explanation:
F(3)=2*3²+3=18=3=21
C is the answer
I would go with A. while it's true that the function continues to increase the function only begins to increase when it's greater then or equal to -8.
we know that having similar triangles so the ratio of sides,area and volume are same.

we know that
will be the area of triangle.

so 
so the ratio of the perimeter of two triangles will be

ratio of the perimeter=
Note:
equals: =
minus: -
q is equal to f minus 3
q = f - 3
q = f - 3 is your equation.
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