49쪽:xy-x+y-1,2ac-5ad+6bc-15bd,2x제곱+xy-y제곱,a제곱+ab-5a-b+4 x제곱+10x+25,4a제곱+4a+1,4x제곱-4xy+y제곱,a제곱-6ab+9b제곱 x제곱-100,a제곱-4분의1b제곱
당신은 어느 그룹입니까?