3x/(x2-1)+(x2-1)/2x=5/2
解方程:1/x2+x +1/x2+3x+2 +1/x2+5x+6 +1/x2+7x+12 +1/x2+9x+20=5/x
解方程:X2--1/8(X2+2X)+X2+2X/3(X2--1)=11
解方程 x2+x-1/(x2+x)=3/2
1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=1/(x+4)
(x2+3x+9)/(x2-27)+(6x)/(9x-x2)-(x-1)/(6+2x)
5x2-3x-5=0,求5x2-2x-1/(5x2-2x)=多少?
1/(x2+x)+1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=4/21
(x2+5x+4)2+2(x2+5x+4)2+1=(x2+.
(-2x2+3x)-[5x-(2x2+1)-x2].
解方程2/x2+x+3/x2-x=4/x2-1
先化简,再求值:(1)2x2-5x x2 4x,其中x=-3 (2)(3x2-xy-2y2)-2(x2 xy-2y2),
2( x2 +1/x2) - 9( x + 1/x) + 14 =