981＋982＋983＋·······987＝984×?

981＋982＋983＋·······987＝984×? 函数y＝x²＋6x＋11的图像经过怎样的一次平移,可以得到y＝x²过程···································· 如果3x＋9.8,那么15x减6等于（ ）·····打错了······················3x＋8等于9,那么15x减6等于（ ） 1＋2＋3+4+5········+n,=多少? 2003/1＋2003/2＋2103/3＋······＋2003/4005 二分之一＋六分之一＋十二分之一＋······＋九十分之一＝? 1/6×7＋1/7×8＋1/8×9＋······＋1/100×101=?请问有什么方法? 已知1＋2＋3＋···＋15＝14400,求2＋4＋6＋···＋30的值 （ 28 ＋ 7分之2 × 8分之7 ） × 4分之1 ＝ ? 高·手·进······················快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快·快 1＋2＋3＋4＋···＋n=? ···· · · · ···· 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? ·········· ··········