No it is not a perfect cube
I won't do this for you, but I can give you a hint. Replace your f variable with -2, -1, 0, 1, and 2. Then take said f variable and put it in your y boxes. Then just get a calculator and do the work on there. It should be pretty easy.
Answer:
Step-by-step explanation:
a= 12 mm ; b = 16 mm ; c = 18 mm
s = (a + b+c)/2

s -a = 18 - 12 = 6 mm
s -b = 18 - 16 = 2 mm
s -c = 18 - 8 = 10 mm



= 5.75
Height = 5.8 mm
Your answer would be -9 & -42.
Here's why ...
(-9)*(-42) A negative times a negative equals a positive (378).
Now, -9-42=-51 & you add these because you have two negatives.
Hope this makes sense & helps you ! (: