✨ ベストアンサー ✨
27⑴ax+x^2+a-1
=(ax+a)+(x^2-1)
=(x+1)a+(x-1)(x+1)
=(x+1)[a+(x-1)]
=(x+1)(x+a-1)
30⑴2x^2+xy-y^2-x+5y-6
=2x^2+(xy-x)-(y^2-5y+6)
=2x^2+(y-1)x-(y-3)(y-2)
=[x+(y-2)][2x-(y-3)]
=(x+y-2)(2x-y+3)
⑵2x^2+5xy+2y^2-x+4y-6
=2x^2+(5xy-x)+2(y^2+2y-3)
=2x^2+(5y-1)x+2(y-1)(y+3)
=[x+2(y-1)][2x+(y+3)]
=(x+2y-2)(2x+y+3)
丁寧にありがとうございます☺️✨