Question

因式分解a^3+2a^2-12a+15

Answer 1

a"' + 2a" - 12a + 15

= a"' + 5a" - 3a" - 12a + 15

= a"( a + 5 ) - 3a" - 15a + 3a + 15

= a"( a + 5 ) - 3a( a + 5 ) + 3( a + 5 )

= ( a + 5 )( a" - 3a + 3 )

或者

= a"' + 125 + 2a" -...