Please help 10 point question!

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

If x-1 and x+3 are the factors of x3+10x2+ax+b find a and b

What is the simplified form of square root of 400 to the 100th power ?