(-2a的m+1次方b的n次方)的2次方(-3a的n次方b)(-a的2次方c)
=(4a的2m+2次方b的2n次方)(-3a的n次方b)(-a的2次方c)
=(-12)a的2m+2+n+2次方b的2n+1次方c
=-12a的2m+n+4次方b的2n+1次方c