关于yx2y5的百科

• .(3x-y)(x+2y)5的展开式中,x4y2的系数为(　　)A.110                  ...

• 问题详情：.(3x-y)(x+2y)5的展开式中,x4y2的系数为()A.110                      B.120                C.130                D.150【回答】.A解析因为(x+2y)5展开式的通项为Tr+1=x5-r(2y)r,故分别令r=2,r=1,可得(...
• 2021-08-215279