답변:(a+b)2=a2+2ab+b2(a-b)2=a2-2ab+b2(a+b)(a-b)=a2-b2(x+a)(x+b)=x2+(a+b)x+ab(ax+b)(cx+d)=acx2+(ad+bc)x+bd
당신은 어느 그룹입니까?