Name a decimal in between 0.4 and 0.5?

Question and answers are in the attached picture. you so much in advance.

Adam plans to choose a video game from the section of the store where everything is 75% off. he writes the expression d-0.75d to find the sale price of the game if the original price is d dollars. gena correctly writes another expression, 0.25d, that will also find the sale price of the game if the original price is d dollars. use the drop down menus to explain each part of adams and rena's expression

Solve the equation by completing the square. x^2+2x=17