设负1≤X≤7,化简√x²-14x+49 减 √x²+2x+1
2(x²-1²)
化简~(x²+3x+9/x²-27)+(6x/9x-x²)-(x-1/6+2x)
已知x+|x|=4.2计算,√x²+3|x|+1,√x²-2|x|+1,越快越好~
7/x²+x+3/x²-x=6/x²-1
x²-1分之x²+x,化简
1/X²+3X+2 +1/X²+5X+6 +1/X²+7X+12 +1/X²+9
已知x²-3x+1=0,求2x^3-3x²-7x+2009,求x²+1/x²+2
1-x²+2xy-y²
计算:[(x²-2x+1)/(x²-1)]÷[(x-1)(x²+x)]-x
(1)(x²-2x)²+2(x²-2x)+1
分解因式(2X²-3X+1)²-22X²+33X-1
因式分解:(2x²-3x+1)²-22x²+33x-1