3/1-x²= 2/1+2x+x²- 5/1-2x+x²用换元法解
5x²+[x²+(5x²-2x)]-2(x²-3x),其中x=-1
x(x²-1)+2x²(x+1)-3x(2x-5)计算
x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x
①2(x+3)(x-3)=x²+(x-1)(x+1)+2x
(x+1-1/1-x)÷(x-x²/x-1) (x-4/x-x-6+ x+2/x-3)÷x+1/x-3
3x²-[5x-(x-2)+2x²]其中x= -1/2
代数式6x+2x²-3x+x²+1,其中x=-5
解方程:x(x+2)+(2x+1)(2x-1)=5(x²+3)
6x+(2x²-3x)-(x²-1)
(2x²-2x+3)(-x³+x-1)
((x²-5x+6)/(12-7x+x²))²÷((x²+3x+2)/(x
x²+3x+9/(x²-27)+6x/(9x-x²)-(x-1)/(6+2x)