Which of these indicates that an id is invalid?

In 2007, americans smoked 19.2 billion packs of cigarettes. they paid an average retail price of $4.50 per pack. a. given that the elasticity of supply is 0.50.5 and the elasticity of demand is negative 0.4−0.4, derive linear demand and supply curves for cigarettes. the demand equation is qdequals=nothingplus+nothing times ×p and the supply equation is qsequals=nothingplus+nothing times ×p.

Alandlord rented an art studio to an artist. under the terms of the signed, written, two-year lease, the artist agreed to pay the landlord $1,000 per month and to assume responsibility for all necessary repairs. after the first year of the lease, the artist assigned the balance of his lease to a sculptor. the landlord approved the sculptor as a tenant and accepted two rent payments from her, and then the landlord sold the building to an investor. the sculptor had made two payments to the investor when an electrical fire broke out in the studio, injuring the sculptor. the fire was caused by faulty wiring. the landlord was aware that there was a dangerous wiring problem when he leased the property to the artist. but when the landlord discovered how costly repairs would be, he decided it would be more profitable to sell the property than to repair it. the problem was not easily discoverable by anyone other than an expert electrician, and the landlord did not tell the artist, the sculptor, or the investor about the problem. the sculptor sues to recover damages for her injuries. from whom can the sculptor recover?

Suppose that electricity producers create a negative externality equal to $5 per unit. further suppose that the government imposes a $5 per-unit tax on the producers. what is the relationship between the after-tax equilibrium quantity and the socially optimal quantity of electricity to be produced?