Consider the following mass distribution, where x- and y- coordinates are given in meters: 5.0 kg at (0.0, 0.0) m, 4.0 kg at (0.0, 7.0) m, and 7.0 kg at (5.0, 0.0) m. Where should a fourth object of 8.0 kg be placed so that the center of gravity of the four- object arrangement will be at (0.0, 0.0) m? Enter the x-coordinate.