Isaiah wants to save up to buy a $325 electronic tablet. He makes $14 per day mowing lawns in his neighborhood. He has $31 already saved. Isaiah wrote an equation to determine how many days he needs to mow lawns before he can afford the tablet. His equation is T=px+r where T is the cost of the tablet and x is the number of days he needs to mow lawns. What is the value of p in his equation? p=