Using the formula Ey,x = -(dy/dx).(x/y), determine the point elasticity of each func- tion below. Specify whether these elasticities are elastic, unit elastic, or inelastic and whether change given different values of x and y. (a) y = 100 - 20x, where x = 4 (b*) y =16 - 8x + x2, where x = 3/2 (c) In(y) = 6 - - In(x), where x = 3 (d*) y = 50x-2, where x = 2