Identity I: $(a + b)^2$ =
Identity II: $(a – b)^2 = a^2 – 2ab + b^2$
Identity III: $a^2 – b^2= (a + b)(a – b)$
Identity IV: $(x + a)(x + b) = x^2 + (a + b) x + ab$
Identity V: $(a + b + c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca$
Identity VI: $(a + b)^3 = a^3 + b^3 + 3a^2b + 3ab^2$
Identity VII: $(a – b)^3 = a^3 – b^3 – 3ab (a – b)$