19
(x+1)÷[2x-(x²+1）/x]
=(x+1)÷[(2x²-x²-1）/x]
=(x+1)×[x/(x²-1)]
=(x+1)×[x/(x-1)(x+1)]
=x/(x-1)
20
x/(x-2)-3/(x+2）=1
[x(x+2）-3(x-2)]/(x²-4）=1
(x²+2x-3x+6)/(x²-4）=1
x²-x+6=x²-4
-x+6=-4
x=10
初二数学计算题和解方程各一题要过程。解方程要写方程两边同乘什么，最后要检验
19
(x+1)÷[2x-(x²+1）/x]
=(x+1)÷[(2x²-x²-1）/x]
=(x+1)×[x/(x²-1)]
=(x+1)×[x/(x-1)(x+1)]
=x/(x-1)
20
x/(x-2)-3/(x+2）=1
[x(x+2）-3(x-2)]/(x²-4）=1
(x²+2x-3x+6)/(x²-4）=1
x²-x+6=x²-4
-x+6=-4
x=10