因式分解多項式！

1. p^2-p-12
=p^2-4p+3p-12
=p (p-4) + 3(p-4)
=(p+3) (p-4)

2.q^2-5q-14
=q^2-7q+2q-14
=q (q-7) +2(q-7)
=(q+2) (q-7)

3.x^2-11x+24
=x^2 -8x- 3x +24
=x(x-8) - 3 (x-8)
=(x-3) (x-8)

4.z^2+4z-77
=z^2+11z-7z-77
=z(z+11) -7(z+11)
=(z-7) (z+11)

5.2b^2+7b+6
=2b^2+4b+3b+6
=2b (b+2) +3(b+2)
=(2b+3) (b+2)

除了這個方法,你也可以用交叉相乘法來計算,這樣我相信在某些情況下,你可以容易一點計算。

希望我可以幫到你!!!!

p^2-p-12
=(p-3)(p+4)

q^2-5q-14
=(q-7)(q+2)

x^2-11x+24
=(x-8)(x-3)

z^2+4z-77
(z-7)(z+11)

2b^2+7b+6
=(2b+3)(b+2)

2010-02-20 20:38:51 補充：
Sorry,第一條WRONG左.......
p^2-p-12
=(p-4)(p+3)

1. p^2-p-12
=p^2-4p+3p-12
=p (p-4) + 3(p-4)
=(p+3) (p-4)

2.q^2-5q-14
=q^2-7q+2q-14
=q (q-7) +2(q-7)
=(q+2) (q-7)

3.x^2-11x+24
=x^2 -8x- 3x +24
=x(x-8) - 3 (x-8)
=(x-3) (x-8)

4.z^2+4z-77
=z^2+11z-7z-77
=z(z+11) -7(z+11)
=(z-7) (z+11)

5.2b^2+7b+6
=2b^2+4b+3b+6
=2b (b+2) +3(b+2)
=(2b+3) (b+2)

除了這個方法,你也可以用交叉相乘法來計算,這樣我相信在某些情況下,你可以容易一點計算。

希望我可以幫到你!!!!

1. p2-p-12
=(p-4)(p+3)

2.q2-5q-14
=(q-7)(q+2)

3.x2-11x+24
=(x-3)(x-8)

4.z2+4z-77
=(x+11)(x-7)

5.2b2+7b+6
=(2b+3)(b+2)