Question 307551
The average change per hour would be indicated by the slope of the line defined by its endpoints: ({{{x[1]}}},{{{y[1]}}}) = (2, 11) and ({{{x[2]}}},{{{y[2]}}}) = (9, -10)
{{{m = (y[2]-y[1])/(x[2]-x[1])}}} Make the appropriate substitutions...
{{{m = (-10-11)/(9-2)}}}
{{{m = (-21)/7}}}
{{{highlight(m = -3)}}}
The average temperature change is -3 degrees fahrenheit per hour.