There were 222 Krispy Kreme Doughnuts stores in the US in 2009 and 294 Krispy Kreme Doughnuts stores in the US in 2015. Write a linear equation in slope-intercept form that models this growth. Let x stand for the number of years after 2009 and let y stand for the number of Krispy Kreme Doughnuts stores in the US.