1、不改变分式的值,使下列分式的份子和分母不含负号
(1)-5y/-x的二次方 (2)-a/2b
(3)4m/-3n (4)-x/2y
(1):(-5y)/(-x)^2=-[5y/x^2]
(2):(-a)/(2b)=-[a/(2b)]
(3):4m/(-3n)=-[4m/(3n)]
(4):-x/(2y)=-[x/(2y)]