3 ms·-1 * -1 = 1 -1 * x = -1 * x + 0 = -1 * x + -x + 1*x = (-1 + 1)*x + -x = -xby nh23423fefe 5y ago-1 * -1 = 1 -1 * x = -1 * x + 0 = -1 * x + -x + 1*x = (-1 + 1)*x + -x = -x