The drawing shows three situations in which a block is attached to a spring. The position labeled "0 m" represents the unstrained position of the spring. The block is moved from an initial position x0 to a final position xf, the magnitude of the displacement being denoted by the symbol s. Suppose the spring has a spring constant of k = 70 N/m. Using the data provided in the drawing, determine the total work done by the restoring force of the spring for each situation. In the case of zero put your result as "+0".