4(x2+3x+1)2-(x2+x-4)2-(x2+5x-16)2
5x2—[x2+(4x—x2)—2(x2—3x)]
先化简,再求值:(x+2x2-2x-x-1x2-4x+4)÷x2-16x2+4x,其中x=2+3.
1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)=1/(x+4)
(x2+5x+4)2+2(x2+5x+4)2+1=(x2+.
解分式方程:2/x2+5x+6 + 3/x2+x-6=4/x2-4
5x2+4-3x2-5x-2x2-5+6x.
解方程2/x2+x+3/x2-x=4/x2-1
化简计算~1/(x2-5x+6) - 1/(4x-x2-3) - 1/(3x-x2-2)
因式分解:(x2+2x+4)(x2+2x-3)-8
3x2-[7x-(4x-3)-2x2]
因式分解 (x2-5x+4)(x2-x-2)-72
证明:根号(x2+2x+4)-根号(x2-x+1)