5.A由题意可得[(x1-5)2+(x2-5)2+(x2-5)2+(x,-5)2+(n-5)2+(x-5)2]=9,则式+理++x2+x+-10×30+150=54,故x+n+x3+x+x+=54-150+300=2046.C1=kg40.4kga70.49=2c=0.3<0.3°=1故c<