落花生文章许地山:一道计算题 急用

来源:百度文库 编辑:高考问答 时间:2024/05/04 23:59:27
-2(1/3 x-3/2 y^2
-2(1/3 x-3/2 y)^2

-2(1/3 x-3/2 y)^2
=-2[(1/9)x^2-2*(1/3)x(3/2)y+(9/4)y^2]
=-2[(1/9)x^2-xy+(9/4)y^2]
=(-2/9)x^2+2xy-(9/2)y^2

右括号在哪里?

-2x/3+3y^2