计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)

来源:学生作业帮助网 编辑:六六作业网 时间:2024/11/06 05:25:55
计算(1)x/x+y-x/x-y(2)a+2+4/a+2(3)x^2-y^2/xy÷(x+y)计算(1)x/x+y-x/x-y(2)a+2+4/a+2(3)x^2-y^2/xy÷(x+y)计算(1)x

计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)
计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)

计算(1)x/x+y-x/x-y (2)a+2+4/a+2 (3)x^2-y^2/xy÷(x+y)
(1)x/(x+y)-x/(x-y)
=x(x-y)/(x+y)(x-y)-x(x+y)/(x+y)(x-y)
=(x^2-xy-x^2-xy)/(x+y)(x-y)
=-2xy/(x+y)(x-y)
(2)a+2+4/(a+2 )
=(a+2)(a+2)/(a+2)+4/(a+2)
=(a^2+4a+4+4)/(a+2)
=(a^2+4a+8)/(a+2)
貌似(2)a+2+4/(a-2 )
=(a+2)(a-2)/(a-2)+4/(a-2)
=(a^2-4+4)/(a-2)
=a^2/(a-2)
(3)(x^2-y^2)/xy÷(x+y)
=(x+y)(x-y)/xy*[1/(x+y)]
=(x-y)/xy

(1)x/x+y-x/x-y=1+y-1-y=0
(2)4+4/5a
(3)x^2-y^2/xy/(x+y)

2x^/(x^-y^), (a^+4a+8)/(a+2)^ 2(x+y)(x-y)/xy÷(x+y)=2(x-y)/xy,这些题目都应该通分计算得来。