中二數學多項式(三)

1. (2a+1)(3a)
= (3a)(2a) + 3a
= 6a^2 + 3a

2. -y(2y^2 - y + 1)
= -2y^3 + y^2 - y

3. 2x(3x+y)
= 6x^2 + 2xy

4. (k+1)(k+2)
= k^2 + k + 2k + 2
= k^2 + 3k + 2

5. (2p-3)(2p+5)
= 4p^2 - 6p + 10p - 15
= 4p^2 + 4p - 15

6. (6+m)(m-4)
= 6m + m^2 - 4m - 24
= m^2 + 2m - 24

7. (2x+y)(3x-2y)
= 6x^2 + 3xy - 4xy - 2y^2
= 6x^2 - xy - 2y^2