python已知列表list_num1=[4,5,7,2,9]和list_num2=[3,6,8]，list_num3=[ ],请将两个列表合并到列表list_num3中，并将合并后的列表中的元素按照

list_num1=[4,7,2,9]
list_num2=[3,6,8]
list_num3=list_num1+list_num2
a=sorted(list_num3,reverse=True)
for n in list_num1:
    print(n,end=" ")
print("\t")
for n in list_num2:
    print(n,end=" ")
print("\t")
for n in  a:
    print(n,end=" ")