Вправи 401 - 500 » 435

Спростіть вираз: 1) 5b/(b-3) – (b+6)/(2b-6) • 90/(b^2+ 6b) = 5b/(b-3) – ((b+6) • 90)/(2(b-3) • b(b+6)) = (5b^(\b))/(b-3) – 45/(b(b-3)) = (5b^2- 45)/(b(b-3)) = (5(b^2- 9))/(b(b-3)) = (5(b-3)(b+3))/(b(b-3)) = (5b+15)/b; 2) (b+2)/(b^2- 2b+1) : (b^2- 4)/(3b-3) – 3/(b-2) = ((b+2) • 3(b-1))/((b-1) • (b-2)(b+2)) – 3/(b-2) = 3/((b-2)(b-1)) – 3^(\b-1)/(b-2) = (6-3b)/((b-2)(b-1)) = (3(2-b))/((b-2)(b-1)) = (-3)/(b-1) = 3/(1-b). Відповідь: 3/(1-b).