Guys please help me on all of these problems

Lines p and q intersect. find the value of b. show your work. cite any theorems you use.

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?

Solve each quadratic equation by factoring and using the zero product property. 14x - 49 = x^2