设函数fx=x2-6x+c1x2-6x+c2x2-6x+c3,集合M=x|{f(x)=0}={x1,x2,x3,x4,x5}⊆N*,设c1≥c2≥c3,则c1-c3等于( )
— I got that job I wanted at the public library.
— ___________! That's good news.
如图所示,人沿水平方向推装满沙子的车,但没有推动,下列说法正确的是( )