This problem requires that you draw the tangent line to the graph at the point x = 2.
You have to use a ruler. Carefully put it in a way that it touches the graph in one and only one point and draw the line.
Extend the line between axis x and y. Then divide the coordinate y by the coordinate x and the quotient is the magnitude of the slope of the tangent line. To account for the sign of the slope keep in mind that if the line goes down from left to right the sign is negative, if the line goes up from left to right the sign is positive.
Here I find that the slope is approximately - 15 cm/s /3kg = - 5 cm/s/kg
