1/（x+2)+1/(x+3)=1/(x+1)+1/(x+4)怎么做

|x+3|-|2x-1|+|x-2|>1怎么做 x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x 2x/(x^2+x)-1/x=5/(x+1)怎么做? [3-2x/1-x]-1=[x+2/x-3]怎么做 (6x+7)(6x+7)(3x+4)(x+1)=6 怎么做啊 2x/3+75%x=1/6怎么做 f(x)=x-ln(1+x)怎么做呢 (x-3)(x+5)-(x+1)²这道题怎么做? lim(sin(x^2*cos(1/x)))/x怎么做? x^4+x^3+x^2+x+1=0,x^2006+x^2005+x^2004+x^2003+x^2002 x+2/x+1-x+3/x+2-x+4/x+3+x+5/x+4 2x^4-x^2-x-5除以x^2+1用多项式除法怎么做,结果是2x^2-x-2-3/(x^2+1)