Someone help me on letter b please! I’m having trouble with with this!

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

Ade and abc are similar. which best explains why the slope of the line between points a and d is the same as the slope between points a and b?

Marquise has 200 meters of fencing to build a rectangular garden. the garden's area (in square meters) as a function of the garden's width w w (in meters) is modeled by: a ( w ) = − w 2 + 1 0 0 w a(w)=−w 2 +100w what side width will produce the maximum garden area? meters