Question

Упростить: (m+1)(m+3)−(1−7m)(1+7m)−(2−m)

Answer 1

Используя: $(a-b)(a+b)=a^2-b^2$

$(m+1)(m+3)-(1-7m)(1+7m)-(2-m)=m^2+3m+m+3-(1-49m^2)-2+m=\\=m^2+3m+m+3-1+49m^2-2+m=50m^2+5m+0=50m^2+5m$