Which of the following equation/s is/are correct?
\(i) (a + b + c)^2 = a^2 + b^2 + c^2 - 2(ab + bc + ca)\)
\(ii) (a + b)^3 = a^3 + b^3 + 3ab(a - b)\)
\(iii) (a − b)^3 = a^3 - b^3 - 3ab(a + b)\)
\(iv) a^2 - b^2 = (a + b)(a - b)\)
We have the following identities:
\((a + b + c)^2 = a^2 + b^2 + c^2 + 2(ab + bc + ca)\)
\((a + b)^3 = a^3 + b^3 + 3ab(a + b)\)
\((a - b)^3 = a^3 - b^3 - 3ab(a - b)\)
\(a^2 - b^2 = (a + b)(a − b)\)