十字相乘法1)(x)^2-5x-12(2)(x)^2-5x-12(3)(x)^2-5x-12(4)(x)^2-5x-12(5)(x)^2-5x-12(6)(x)^2-5x-12(7)(x)^2-5x-12(8)(x)^2-5x-12(9)(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12(x)^2-5x-12

十字相乘法
1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)