已知,-2已知,-2已知,-2-25a+7b=(a-b)+(a+2b)×4-2+1×4<(a-b)+(a+2b)×4<-1+3×42<(a-b)+(a+2b)×4<112<5a+7b<11
已知,-2-2
5a+7b=(a-b)+(a+2b)×4-2+1×4<(a-b)+(a+2b)×4<-1+3×42<(a-b)+(a+2b)×4<112<5a+7b<11