(m+1)(m+3)-(1-7m)(1+7m)-(2-m) у

m²+3m+m+3-1-7m+7m+49-2+m=m²+5m+49

Пошаговое объяснение:

(m + 1)(m + 3) - (1 - 7m)(1 + 7m) - (2 - m) = m² + 3m + m + 3 - (1 - 49m²) - 2 + m = m² + 3m + m + 3 - 1 + 49m² - 2 + m = 50m² + 5m + 0 = 50m² + 5m