(a + b)^2 =
a^2 + 2*a*b + b^2
(a - b)^2 = a^2 - 2*a*b + b^2
(a + b + c)^2 = a^2 + b^2 + c^2 + 2*(ab + bc + ca)
(a + b)^3 = a^3 + b^3 + 3*a*b*(a + b)
(a - b)^3 = a^3 - b^3 - 3*a*b*(a - b)
(a + b + c)^3 = a^3 + b^3 + c^3 + 3*(a + b)*(b + c)*(c + a)
(a + b)^2 = (a - b)^2 + 4*a*b
(a - b)^2 = (a + b)^2 – 4*a*b
a^2 – b^2 = (a + b)(a - b)
(a - b)^2 = a^2 - 2*a*b + b^2
(a + b + c)^2 = a^2 + b^2 + c^2 + 2*(ab + bc + ca)
(a + b)^3 = a^3 + b^3 + 3*a*b*(a + b)
(a - b)^3 = a^3 - b^3 - 3*a*b*(a - b)
(a + b + c)^3 = a^3 + b^3 + c^3 + 3*(a + b)*(b + c)*(c + a)
(a + b)^2 = (a - b)^2 + 4*a*b
(a - b)^2 = (a + b)^2 – 4*a*b
a^2 – b^2 = (a + b)(a - b)
a^3 + b^3 =
(a + b)(a^2 + b^2 - ab)
a^3 – b^3 =
(a - b)(a^2 + b^2 + ab)
a^3 + b^3 +c^3 – 3*a*b*c = (a + b + c)*(a^2 + b^2 + c^2 - a*b - b*c - c*a)
a^n
+ b^n is divisible by (a + b), when n is odd.
a^n
+ b^n is not divisible by (a + b), when n is even.
a^n
+ b^n is not divisible by (a - b).
a^n
- b^n is always divisible by (a - b).
a^n
- b^n is not divisible by (a + b), when n is odd.
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