Anybody wanna join my zm? It’s just me and my 2 other friends, we are bored as fawk

It says factor each expression 49x-28?

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 equivalent to 5a/4 - b/8 ?