a-b=-3,a+c=5,则代数式ac-bc+a^2-ab的值是

问题描述:

a-b=-3,a+c=5,则代数式ac-bc+a^2-ab的值是

ac-bc+a^2-ab
=c(a-b)+a(a-b)
=(a+c)(a-b)
=13*5
=-15

(a-b)*(a+c)=ac-bc+a^2-ab=-3*5=-15

ac-bc+a^2-ab
=(ac-bc)+(a^2-ab)
=c(a-b)+a(a-b)
=(a-b)(a+c)
=-15

-15,(a-b)(a+c)=ac-bc+a^2-ab