Вправи 201 - 300 » 212 (1-7)

212. Виконайте ділення: 1) 1/a : 1/b = 1/a • b/1 = b/a; 2) 2/x : 2/y = 2/x • y/2 = (2 •y)/(x •2) = y/x; 3) 1/2x : 1/2y = 1/2x • 2y/1 = 2y/2x = y/x; 4) 1/2x : 2/y = 1/2x • y/2 = y/(2x •2) = y/4x; 5) 2x/3 : 2y/5 = 2x/3 • 5/2y = (2x •5)/(3 •2y) = 5x/3y; 6) 1/3xy : 5/9x = 1/3xy • 9x/5 = 9x/(3xy •5) = 3/5y; 7) 1/5x : 2/15xy = 1/5x • 15xy/2 = 15xy/(5x •2) = 3y/2;