I need help with this problem

Which function is shown in the graph below?

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula,equation,to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

Issof claims that the scale factor is 1/2. which statement about his claim is correct