规定a*b=(a+2)(b+5)-(a+3)(b+4).化简:(m+1)*(n+1)
问题描述：
规定a*b=(a+2)(b+5)-(a+3)(b+4).化简:(m+1)*(n+1)
答
(m+1)*(n+1)
=(m+1+2)(n+1+5)-(m+1+3)*(n+1+4)
=(m+3)(n+6)-(m+4)*(n+5)
=mn+6m+3n+18-mn-5m-4n-20
=m-n-2
答
a*b=(a+2)(b+5)-(a+3)(b+4)=a-b-2
所以:(m+1)*(n+1)=m+1 -(n+1)-2=m-n-2
答
(m+1)*(n+1)=(m+1+2)(n+1+5)-(m+1+3)(n+1+4)
=(m+3)(n+6)-(m+4)(n+5)=mn+3n+6m+18-mn-4n-5m-20
=m-n-2