A:6
B:9
C:12
D:15
____+5=10+3
①(2a-3)(3a-1)=6a2-11a+3;②(m+n)(n+m)=m2+mn+n2;③(a-2)(a+3)=a2-6;④(1-a)(1+a)=1-a2.
— will the 6th Chinese Film Festival in France last?
—From May 24th to July 19th.