初三数学代值计算当x/y=3/4时,求分式(xy+y^2)/(x^2-xy)的值

Question

初三数学 代值计算
当x/y=3/4时,求分式(xy+y^2)/(x^2-xy)的值

Answer 1

分式(xy+y^2)/(x^2-xy)
=(x/y+1)/[(x/y)^2-x/y] (分子分母同时除以 y^2)
=(3/4+1)/(9/16-3/4) (代值)
=(7/4)/(-3/16)
=-28/3