— It's too hot. Would you mind _______ the door?
—_______, please do it now.
A:to open; OK
B:opening; Certainly not
C:opening; Of course
D:to open; Good idea
计算:
(1)若xm•x2m=2,求x9m的值;
(2)已知3×92m×27m=315,求m的值.
函数f(x)=x2-3x+2的零点是( )