Odpowiedź:
a) (3c + 5a)(4 + 2a) =
= 12c + 6ac + 20a + 10a² =
b) (x – 2)(x – 3) =
= x² - 3x - 2x + 6 =
= x² - 5x + 6
c) (a + 5b – 4)(3 + 2a) =
= 3a + 2a² + 15b + 10ab - 12 - 8a =
= -5a + 2a² + 15b + 10ab -12
d) (a + 10)(a – 5)(a + 20) =
= (a² - 5a +10a -50)(a+20) =
= (a² + 5a -50)(a+20) =
= a³ + 20a² + 5a² + 100a - 50a - 1000 =
= a³ + 25a² + 50a - 1000
