Can I please please get help with this?

What is the common difference in the following arithmetic sequence? 7,3,-1,-5

Lindsay used two points, (x,y; ) and (+2.82), to find the equation of the line, y = mx + b, that passes through the points. y2-y, first, she used the definition of slope and determined that the value of mis x, - . given this information, which expression must represent the value of b?

If p(a) = 0.70 and p(b) = 0.20, then a and b are independent events if