Another special feature of the linear supply curve arises because its elasticity can also be written as bP/(a + bP), which is less than 1 if "a < 0" and greater than 1 if "a > 0". Linear supply curves which cut through the positive part of the price axis and have zero quantity supplied if the price is too low ("P < -a/"b) have "a < 0" and hence they always have elastic supply. Curves which cut through the positive part of the quantity axis and have positive quantity supplied ("Q = a") even if the price is zero have "a > 0" and hence always have inelastic supply. Curves which go through the origin have "a = 0" and hence have an elasticity of 1.