Вправа 101 - 200 » 152

152. Подайте у вигляді дробу або одночлена вираз. a) 2/3a + 4/3a – (6- a^2)/3a = (2+4-6+ a^2)/3a = (6-6+ a^2)/3a = a^2/3a = a/3; б) (2a+3)/5b + (2a-9)/5b + (a+1)/5b = (2a+3+2a-9+a+1)/5b = (5a-5)/5b = (5(a-1))/5b = (a-1)/b; в) x^2/(x+1) + (2x-1)/(x+1) + (1-x)/(x+1) = (x^2+ 2x-1+1-x)/(x+1) = (x^2+ x)/(x+1) = = (x(x+1))/(x+1) = x; г) (2(m+n))/(m-n) – m/(m-n) – m/(m-n) = (2m+2n-m-m)/(m-n) = 2n/(m-n).