What values of a and b will make the equation CD = I true?

Barney & noblet customers can choose to purchase a membership for $25 per year members receive 10% off all store purchases 1. how much would a member pay per year if he bought $50 worth of items each year? 2. write a slope-intercept equation that expresses how much a member pays per year using x to represent his purchases per year 3. how much would a member have to spend per year to pay off his membership fee?

Which expression is the factorization of x^2+10+21

Can someone me with this graph problem by the way i need to know the answers by today since this assignment is due ! !