What's the selling price if the markup is 45% and the cost to store 130

Which of the following is true for the relation f(x)=2x^2+1

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?