Answer:
In most cases, the supply curve is drawn as a slope rising upward from left to right, since product price and quantity supplied are directly related (i.e., as the price of a commodity increases in the market, the amount supplied increases).
Since slope is defined as the change in the variable on the y-axis divided by the change in the variable on the x-axis, the slope of the supply curve equals the change in price divided by the change in quantity.
Supply curves from profit-maximizing firms can be vertical, horizontal or upward sloping. While it is possible for industry supply curves to be downward sloping, supply curves for individual firms are never downward sloping.
