5x2+4-3x2-5x-2x2-5+6x.
5x2+4-3x2-5x-2x2-5+6x.
5x2—[x2+(4x—x2)—2(x2—3x)]
解分式方程:2/x2+5x+6 + 3/x2+x-6=4/x2-4
解方程:1/x2+x +1/x2+3x+2 +1/x2+5x+6 +1/x2+7x+12 +1/x2+9x+20=5/x
1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=1/(x+4)
(-2x2+3x)-[5x-(2x2+1)-x2].
化简求值:3x2+(2x2-3x)-(-4x+5x2),其中x=2010.
化简计算~1/(x2-5x+6) - 1/(4x-x2-3) - 1/(3x-x2-2)
1/(x2+x)+1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=4/21
用换元法解方程x2-3x+5+6/(x2-3x)
不等式:(x2+3x+3)/(x2+2x+5)
因式分解 (x2-5x+4)(x2-x-2)-72