What kinda of method is it your using?

Justin has 750 more than eva and eva has 12 less than justin together they have a total of 63 how much money did

Campus rentals rents 2 and 3 bedrooms apartments for $700 ans $900 a month respectively. last month they had six vacant apartments and reported $4600 in lost rent. how many of each type of apartment were vacant?

Which function represents the sequence? f(n)=n+3 f(n)=7n−4 f(n)=3n+7 f(n)=n+7