简算 11/18x3/14x21/55
2/1X3+2/3X5+2/5x7+.+2/19x21
1/1X3+1/3X5+1/5X7...1/17X19+1/19X21=
(2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==?
2/1X3+2/3X5+2/5x7+.+2/19x21全过程(最好带原因),
min=2*x11+x12+3*x13+x14+2*x15+4*x21+2*x22+x23+3*x24+x25+2*x3
3连跨,18米X21米X18米钢结构厂房,两边5吨吊车,中间15吨吊车,檐口高度11米,起吊高度8米左右.
计算 45/49x21/25= 75除15/16= 7/9除14= 11/22除33/48= 5/27除25/36= 3
66x21十19x21十85x19=?求简算!
66X21+19X21+85X19怎么简便计算?
66X21+19X21+85X19的简便方法计算
纯棉 21x21 60x58 48’
Lingo程序中,a=@if(x11-x21#ge#0,0,x21-x11)是什么意思?