Develop using squaring rules and then simplify the expression as far as possible
(x + 1)^3 - (3x + 1)
Not sure what "squaring rules" are, but using the Binomial Theorem,
(x + 1)^3 - (3x + 1)
= x^3 + 3x^2 + 3x + 1 - 3x - 1
= x^3 + 3x^2
= x^2 (x+3)