Question

若规定a*b=（a+1）（b+4）—（a+2）（b+3）.请化简（m+1）*（n—1）,并求当m=2006,n=2005

Answer 1

m+1=a 则m=a-1

n-1=b则n=b+1代入到原式a*b=(a+1)(b+4)-(a+2)(b+3)

则（m+1)(n-1)=(a-1+1)(b+1+4)-(a-1+2)(b+1+3)

=a*(b+5)-(a+1)(b+4)

=ab+5a-(ab+4a+b+4)

=a-b-4

=m+1-(n-1)-4

=m+2-n-4

=2006-2005+2-4

=-1