What does b stand for in the equation y=mx+b

On a coordinate grid, point p is at (4, 3) and point r is at (−2, −5). points q and s are a reflection of both points across the x-axis. what are the coordinates of q and s? q(−4, 3), s(2, −5) q(4, −3), s(−2, 5) q(−4, −3), s(2, 5) q(−4, 3), s(−2, 5) ; -; i can't figure it out, if someone can me with the answer, that would be nice

What is the value of x in the diagram below?

Which function has the domain x> -11?