Question

a3-b3=3a2b-3ab2+1其中啊a,b为实数,则a-b=?

Answer 1

a^3-b^3=3a^2b-3ab^2+1

(a-b)(a^2+ab+b^2)-3ab(a-b)=1

(a-b)(a^2-2ab+b^2)=1

(a-b)^3=1

a-b=1