日常生活中经常使用的电源主要有______、蓄电池和________

A．保护

B．装饰

C．标识

D．防腐（特殊功能)

A．二

B．八

C．十

D．十六

A、恒功率

B、直线型

C、恒转矩

D、离心机型

现有数值如下:123,86,-89,48,44,-85,-2,-9,-186,-33,-65,-76,168,-55,-174,102,-21,1,-126,-5,170,13,18,-142,-314,51,-15,-94,145,-40,67,134,-75,103,-23,59,0,-141,132,-68,77,112,93,10,-19,-39,-86,68,-55,-30,106,-120,155,-43,-5,-95,-122,212,143,-18,-44,-44,-59,141,162,139,-16,-80,-99,25,17,11,-60,14,51,96,123,57,-102,95,-6,-94,122,72,76,74,152,18,-28,-113,82,-140,211,60,-261,-145,7,14,63,-91将其转为20行5列的矩阵,对其每行内容求和,筛选出求和列中大于等于75%分位的所有行,则这些行中所有数值的总和是多少 计算过程中所有数据位浮点数,保持2位小数!