Вправи 101 - 200 » 168 (1-2)

168. Виконайте дії: 1) (b+4)/(b^2- 6b+9) : (b^2- 16)/(2b-6) – 2/(b-4) = ((b+4) •2(b-3))/((b-3)^2 (b-4)(b+4)) – 2/(b-4) = 2/((b-3)(b-4)) – 2^(\b-3)/(b-4) = (2-2(b-3))/((b-3)(b-4)) = (2-2b+6)/((b-3)(b-4)) = (8-2b)/((b-3)(b-4)) = (-2(b- 4))/((b-3)(b-4)) = –2/(b-3) = 2/(3-b); 2) ((m- 1^(\m-1))/(m+1) – (m+ 1^(\m+1))/(m-1)) : 4m/(m^2- 1) = ((m-1)^2- (m+1)^2)/((m+1)(m-1)) • ((m^2- 1))/4m = (m^2- 2m+1- m^2- 2m-1)/((m+1)(m-1)) • ((m-1)(m+1))/4m = (-4m(m-1)(m+1))/((m+1)(m-1) • 4m) = –1;