The equation y=20x+100 represents the membership at a local gym where y represents the total number of members and x represents the number of weeks the gym has been open. What does the
y-intercept represent in this equation?

  The number of members when the gym opened.

Step-by-step explanation:

The y-intercept is the value of y when x = 0. Since x is the number of weeks the gym has been open, x = 0 represents the time when the gym has been open 0 weeks: the point in time that the gym opened.

Since y represents the membership, the y-intercept represents the membership at the time the gym opened.