Respuesta :
Okay so to model the number of messages first you'd take the values and make an equation, so the school receives 2000 email messages and out of those messages 1250 are junk mail so 2000=1250+x , x represents the number of emails that are not junk mail so we subtract 1250 from 2000 to get 750 so 2000=1250+750 is the equation.