the demand for a product is f(p)=a-bp, where f(p) is quantity demanded per day and p is the price per unit sold.

a) calculate the point price elasticity: my response: please correct if is wrong: e=f'(p)(p/f(P))=-b/(a-bp/p)=-b/(a/p)-b

b) this i can not figure it out: determine the value of p that will make price elasticity of demand equal 2.

thank you

helen