(a + b)^3 = a^3 + 3a^2b + 3ab^2+ b^3
(a +(- b))^3 = (a-b)^2 = a^3 - 3a^2b + 3ab^2- b^3
it's x ≤ 3 :))) I found it out after realizing what you were asking
Answer:

Step-by-step explanation:
An arithmetic sequence that is described by the explicit formula ...

can also be described by the recursive formula ...

Matching parts of the formulas, we see that a1 = 4, d = -7. Putting these values into the explicit formula gives ...
