maths: a^3 plus b^3?

(a^3 + b^3)=(a+b)(a^2 -ab +b^2)
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(a+b)^3=a^3 + 3a^2b + 3ab^2 +b^3

1)
x^3 + y^3 = (x + y)(x^2 - xy + y^2) (<== formula)
a^3 + b^3 = (a + b)(a^2 - ab + b^2)

2)
(a + b)^3
= (a + b)(a + b)(a + b)
= (a*a + b*a + a*b + b*b)(a + b)
= (a^2 + ab + ab + b^2)(a + b)
= (a^2 + 2ab + b^2)(a + b)
= a^2*a + 2ab*a + b^2*a + a^2*b + 2ab*b + b^2*b
= a^3 + 2a^2b + ab^2 + a^2b + 2ab^2 + b^3
= a^3 + 2a^2b + a^2b + ab^2 + 2ab^2 + b^3
= a^3 + 3a^2b + 3ab^2 + b^3

uhm... what does a and b equal?

a^3+b^3=(a+b)(a^2-ab+b^2)
(a+b)^3=(a+b)(a^2+2ab+b^2)=
a^3+3a^2b+3ab^2+b^3

a^3 plus b^3 = a^3 + b^3

you cannot add both since they are not similar terms

on the other hand,

(a+b)^3 = a^3 + 3a^2 b + 3ab^2 + b^3