1. (a±b)^2=a^2±2ab+b^2 (複号同順)
2. (a+b)(a-b)=a^2-b^2
3. (x+a)(x+b)=x^2+(a+b)x+ab
4. (ax+b)(cx+d)=acx^2+(ad+dc)x+bd
5. (a±b)^3=a^3±3a^2b+3ab^2±b^3 (複号同順)
6. (a±b)(a^2干ab+b^2)=a^3±b^3 (複号同順)
7. (a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ca
註：＾はべき乗です
