I need help with math Please?

[flight m]

I need help with quadratic equations and inequalities?
1) A rectangular courtyard is to have a rectangular section of grass in its middle surrounded by a planted section of uniform width. The grassed area is to be twice the planted area. The outer dimensions of the courtyard, including the grass and the planted border, are 50 m by 30. Which of the following would be a suitable equation for finding the width w of the planted section?
A) (50-2w)(30-2w)=3000
B) (50-2w)(30-2w)=1000
C) (50-w)(30-w)=3000
D) (50-2w)(30-2w)=1500

2) Find the Solution set. 3x^2-15x=0


3)When a baseball is hit, the height of the ball h(t), at any time t>_ ( great or then) 0, is determined by the equation h(t)=-12x^2+44t+6. Determine the time the ball's height is exactly 46ft.

4) A square and a rectangle have the same width. The rectangle's length is 1cm more than twice its width. If one area decreased by the other is 56 square centimeters, what is the area of the rectangle?

Please help me and explain how you came up with the answer.