Here's link to the answer:
cutt.us/tWGpn
Step-by-step explanation:
We have

First, 125 is a perfect cube because

and
x^3 is a perfect cube because

so we can use the difference of cubes identity

Let say we have two perfect cubes:
64 because 8×8×8=64
and 27 because 3×3×3=27 and let subtract

we know that

but using the difference of cubes identity we should get the same thing.
Remeber cube root of 64 is 4 and cube root of 27 is 3 so we have


So the difference of cubes works for real numbers. This is a good way to help remeber the identity using real numbers.
Back on to the topic,
we know that 5 is cube root of 125 and x is the cube root of x^3 so we have


X + x + 1 + x + 2 + x + 3 = 330
4x + 6 = 330
4x = 324, x = 81
Smallest number: 81
Biggest number: 81 + 3 = 84
Sum: 81 + 84 = 165
The answer is 165
7,440 I believe, all you need to use is basic subtraction for this.