y = x2 - 2x - 3, Then \(\frac{\delta y}{\delta x} = 2x - 2\) But at minimum point,\(\frac{\delta y}{\delta x} = 0\), Which means 2x - 2 = 0 2x = 2 x = 1. Hence the minimum value of y = x2 - 2x - 3 is; ymin = (1)2 - 2(1) - 3 ymin = 1 - 2 - 3 ymin = -4