Odpowiedź:
zad 1
(4c - 5d)(c + 1) = 4c² - 5cd + 4c - 5d
Odp: D
zad 2
(4x + 3)(5 - x) = 20x + 15 - 4x² - 3x = - 4x² + 17x + 15
Odp: C
zad 3
a) (4a + 3)(b + 5) = 4ab + 3b + 20a + 15 = 20a + 4ab + 3b + 15
b) (5a - b)(a - 3) = 5a² - ab - 15a + 3b = 5a² - 15a - ab + 3b
c) (3x - y)(2x + y) = 6x² - 2xy + 3xy - y² = 6x² + xy - y²
d) (2xy + 3x)(xy - 2x) = 2x²y² + 3x²y - 4x²y - 6x² = - 6x² - 2x²y + 2x²y²
