(-5p+2m)*2-(-3m+5p)(5p+3m)+20pm = 2 (-5р+2m) - ( -3m+5p)(5p+3m) + 20pm = -10p + 4m - ( -3m(5p+3m) + 5p(5p+3m)) + 20pm= -10p + 4m - (-15mp - 9m² + 25p² + 15pm) + 20pm = -10p + 4m - 15pm + 9m² - 25p² - 15pm + 20pm = -10p + 4m - 10pm + 9m² - 25p²
