✔ 最佳答案
1) x3 - abx - x2y + ax2 - bx2 + bxy
= x (x2 - ab - xy + ax - bx + by)
= x (x2 - xy + ax - bx + by - ab )
= x (x - b) (x - y + a)
2) abx2 + aby2 + a2xy + b2xy
= a2xy + abx2 + aby2 + b2xy
= ax (ay + bx) + by (ay + bx)
= (ax + by) (ay + bx)
3) 9c2 - 4l2 + 16lm - 16m2
= 9c2 - 4(l2 - 4lm + 4m2)
= 9c2 - 4(l - 2m)2
= [3c + 2(l - 2m)] [3c - 2(l - 2m)]
或[3c + 2(l - 2m)] [3c + 2(2m - l)]
4) (x2 + x)2 - 18(x2 + x) + 72
= [(x2 + x) - 6] [(x2 + x) - 12]
= (x2 + x - 6) (x2 + x - 12)
= (x + 3) (x - 2) (x + 4) (x - 3)
5) a2-4a(x - y)-5(x - y)2
= [a + (x - y)] [a - 5(x - y)]
= (a + x - y) [a + 5(y - x)]
