(2008?顺义区二模)设 依题意,得xx?1=1-x?5x2?1,方程两边都乘以(x+1)(x-1)去分母,得x(x+1)=x2-1-(x-5),去括号,得,x2+x=x2-1-x+5,移项、合并同类项,得2x=4,系数化为1,得,x=2,检验:当x=2时,(x+1)(x-1)=(2+1).
董存瑞的故事
(2008?顺义区二模)设 依题意,得xx?1=1-x?5x2?1,方程两边都乘以(x+1)(x-1)去分母,得x(x+1)=x2-1-(x-5),去括号,得,x2+x=x2-1-x+5,移项、合并同类项,得2x=4,系数化为1,得,x=2,检验:当x=2时,(x+1)(x-1)=(2+1).
董存瑞的故事