carilah hasil dari : 1. 2a(7a^2 + 4b 2. -2mn(3m^2 - 4mn - 7n^2) 3. (4x + 3) (5x - 3) 4. (2a - 5) (2a - 9) tolong di jawab yaa

1. 2a(7a^2 + 4b)
= 14a^3 + 8ab

2. -2mn(3m^2 - 4mn - 7n^2)
= -6m^3n + 8m^2n^2 + 14mn^3

3. (4x + 3) (5x - 3)
= -20x^2 - 12x + 15x - 9
= -20x^2 + 3x - 9

4. (2a - 5) (2a - 9)
= 4a^2 - 18a - 10a + 45
= 4a^2 - 28a + 45

Maaf kalau salah