Odpowiedź:
a) 2x(x - 4) - 5x = 2x × x - 2x × 4 - 5 = 2x² - 8x - 5x = 2x² - 13x
b) 7x - 3(x +8) = 7x -3 × -x - 3 × 8 = 7x -3x - 24 = 4x - 24
c) 2x(a - 3) + 4(x - 2) = 2x × a - 2x × 3 + 4 × x - 4 × 2 = 2ax - 6x + 4x - 8 = 2ax - 2x - 8
d) -4x(5 + 2x) + 2x(-2x - 5) = -20x - 8x² - 4x² - 10x = -30x - 12x²
