灵鹊做题网解不等式1−x3≤1−2x7
利用不等式的基本性质：先去分母，再去括号，再移项合并同类项，最后系数化1即可解答．
解不等式x−1≤1+x3，并把解在数轴上表示出来．
2/1x3+2/3X5+2/5x7=2/7x9+2/9x11
2/1X3+2/3X5+2/5x7+.+2/19x21
1+2X3+4X5+6X7+8X9=303
x8+x7+x6+x5+x4+x3+x2+x+1因式分解
解不等式组x+6≤3x+41+2x3＞x−1.
1x2/1+2x3/1+3x4/1+4x5/1+5x6/1+6x7/1
1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7
2/1X3+2/3X5+2/5x7+.+2/19x21全过程（最好带原因）,
-13x3/2+3/1x(-13)-0.34x7/2-7/5x0.34用简便方法计算
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
1+2x3+4x5+6x7+.50x51的和是奇数还是偶数?写出原因