A:Heard it
B:Made it
C:Got it
D:Taken it
There _____________ many people in the park.
5×25= ____
4×38= ____
3×512= ____
2×34= ____
先化简,再求值:x2-1x-12﹣xx-1÷12x,请选取一个适当的x的数值代入求值.