Nas equacoes do segundo grau: x ao quadrado +9=0 e x ao quadrado menos 3x=0 i as duas equacoes possuem raizes reais ii apenas uma das equacoes pode ser resolvida no conjunto dos numeros reais iii nenhuma das equacoes tem solucao no conjunto dos numeros reais iv para obter a solucao de uma das equacoes é preciso recorrer ao conjunto dos numeros complexos. quais dessas sao corretas?

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?

If the perimeter of the garden is 37 ft. the width is x and the length is 15 ft. what is the width of the garden in feet?