把x4﹣3x3﹣28x2因式分解,结果为 [ ]
A.x2(x﹣4)(x+7)
B.x2(x+4)(x﹣7)
C.x2(x﹣4)(x﹣7)
D.x2(x+4)(x+7)
答案:B
A.F1<F2
B.F1=F2
C.t1>t2
D.t1<t2
若函数y=mxm2+3m-1是反比例函数,求m的值.