Write a system of equations to describe the situation below, solve using substitution, and fill in the blanks.
Clare has a home-based business making and selling scented soaps. She intially spent $65 to
purchase soap-making equipment, and the materials for each kilogram of soap cost $16.
Clare sells the soap for $21 per kilogram. Eventually, she will sell enough soap to cover the
cost of the equipment. How much soap will that be? What will be Clare's total sales and costs
be?