y = 1/4 x - 2
=> a linear function => a straigh line
=> slope = the coefficient of x => slope = 1/4
=> x = 0 => the y-intercept = -2
=> y = 0 => 0 = 1/4 x - 2 =>x = 8 => point (8,0)
With all that information you can identify the graph because it is a straight line that passes through (0,-2) and (8,0), its inclination (slope) is 1/4, and the graph goes through the quadrants I, III and IV (there are no points in the quadrant II)..