Question

Упр 3 только :)))))))​

Answer 1

Ответ:

$(1-ab)^3=(1-ab)(1-ab)^2=(1-ab)(1-2ab+a^2b^2)=1-3ab+3a^2b^2-a^3b^3\\\\\\{}\ \ \ 1-ab\\\times (1-2ab+a^2b^2)\\{}---------------\\{}\ \ \ \ 1-2ab+a^2b^2\\{}+\ \ (-ab+2a^2b^2-a^3b^3)\\{}---------------\\{}1-3ab+3a^2b^2-a^3b^3$