其实如果你公式记不下来的话,你要懂得变通,比如(a-b)^3=(a-b)^2×（a-b）=(a^2-2ab+b^2)(a-b)=a^3-a^2b-2a^2b+2ab^2+ab^2-b^3=a^3-b^3-3a^2b+3ab^2（a-b）^4=(a-b)^3*(a-b)=(a^3-b^3-3a^2b+3ab^2)(a-b)=a^4-a^3b-ab^...