(2х – у)² – (у + 2х)² = 4х²-4ху+у² - (у²+4ху+4х²) = 4х²-4ху+у² - у²-4ху-4х²= - 8ху

х = –1 1/3, у= 3/4

-8 * (–1 1/3) * 3/4 =

1)-8 * (–1 1/3) = - 8/1 * (- 4/3) = 32/3 = 10 2/3

2) 10 2/3 * 3/4 = 32/3 * 3/4 = 8

Ответ : 8