Подобных членов. (12c+-7d)= (11x^2--x^2)= (13x-11y++10y-15z)= (7m^2-4mn--mn+2n^2)= (1/2x+2/3y-1//3x-1/2y+1/4z)= (1/5ab+1/7bc-2//5ab-3/14bc-1/5ac)= (2/3x^3-3x^2y+1/4xy^2-2y^3--2/3+1/2y^3-1/3x^2y-2xy^2)= (0,6ab-0,5bc+,5ab+2,5bc-cd)= (0,5abc+0,3bcd-1,,5abc+0,6bcd-2acd)= нужно