化简:(5x+2x2)+(1–5x–3x2)
解方程:1/x2+x +1/x2+3x+2 +1/x2+5x+6 +1/x2+7x+12 +1/x2+9x+20=5/x
(-2x2+3x)-[5x-(2x2+1)-x2].
5x2—[x2+(4x—x2)—2(x2—3x)]
(x+1)2-2(x2-1)+(x-1)² (x2-3x+1)(x2-3x-3)-5 因式分解
1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=1/(x+4)
不等式:(x2+3x+3)/(x2+2x+5)
(x2+5x+2)(x2+5x+3)-12怎么因式分解 (x2)是x的平方,
5x2-3x-5=0,求5x2-2x-1/(5x2-2x)=多少?
化简计算~1/(x2-5x+6) - 1/(4x-x2-3) - 1/(3x-x2-2)
先化解,再求值:【1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)】/1/(x2+9x+20),
1/(x2+x)+1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=4/21
x2-5x+1=0则x2+x2/1