因式分解練習

1.6x - 3x^2 + x^3 - 18
=x^3 - 3x^2 + 6x - 18
=x^2(x - 3) + 6(x - 3)
=(x - 3)(x^2 + 6)

2.-1 + 49a^2
=49a^2 - 1
=(7a + 1)(7a - 1)

3.48p^2 - 3q^2
=3(16p^2 - q^2)
=3(4p + q)(4p - q)

4.c^2 + 18c + 81
=(x + 9)^2

5.-8r^2 + 24r - 18
=-2(4r^2 - 12r + 9)
=-2(2r - 3)^2
=2(2r - 3)(3 - 2r)

6.z^2 - 3z - 10
=(x - 5)(x + 2)

7.k^2 - 13k + 42
=(k - 7)(k - 6)

8.ac -b^2c - 2ab^2 + 2a^2
=c(a - b^2) - 2a(b^2 - a)
=c(a - b^2) + 2a(a - b^2)
=(a - b^2)(c + 2a)

9.6ax + 4bx - 2cx - 3ay - 2by + cy
=6ax - 3ay + 4bx - 2by - 2cx + cy
=3a(2x -y) + 2b(2x - y) - c(2x - y)
=(2x - y)(3a + 2b - c)