因式分解:(1)x^2+8x+15; (2)t^2-7t+6; (3)x^2+2x-15; (4)a^2-4a-21_数学解答

因式分解:(1)x^2+8x+15; (2)t^2-7t+6; (3)x^2+2x-15; (4)a^2-4a-21

人气：184 ℃　时间：2020-05-10 11:56:46

解答

1)x^2+8x+15=(x+3)(x+5)
(2)t^2-7t+6=(t-1)(t-5)
; (3)x^2+2x-15=(x-3)(x+5)
; (4)a^2-4a-21=(x-7)(x+3)