Question

(a-b)²
(a+b)³
(a-b)³

Answer 1

$(a-b)^{2}=a^{2}-2ab+b^{2}$
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$(a+b)^{3}=(a+b)(a+b)^{2}\\(a+b)^{3}=(a+b)(a^{2}+2ab+b^{2})\\(a+b)^{3}=a^{3}+2a^{2}b+ab^{2}+a^{2}b+2ab^{2}+b^{3}\\(a+b)^{3}=a^{3}+3a^{2}b+3ab^{2}+b^{3}$
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$(a-b)^{3}=(a-b)(a-b)^{2}\\(a-b)^{3}=(a-b)(a^{2}-2ab+b^{2})\\(a-b)^{3}=a^{3}-2a^{2}b+ab^{2}-a^{2}b+2ab^{2}-b^{3}\\(a-b)^{3}=a^{3}-3a^{2}b+3ab^{2}-b^{3}$