Вправи 401 - 500 » 407

Спростіть вираз: 1) 6b2 ∙ (5b^2- 4)/3 + 20b ∙ (3b - 2b^3)/4 = 2b2 ∙ (5b2 – 4) + 5b ∙ (3b – 2b3) = 10b4 – 8b2 + 15b2 – 10b4 = 7b2; 2) 14m ∙ (m + n)/7 – (m - n)/8 ∙ 16n – 2(m2 + n2) = 2m(m + n) – 2n(m – n) – 2(m2 + n2) = 2m2 + 2mn – 2mn + 2n2 – 2m2 – 2n2 = 0.