I'm Back and I am desperate!!

I said I would be back and here I am! I am really confused and I need help fast because my work is due in a few hours. :confused: Ok, here we go...

1. D=c-s/n (for depreciation)

2. A=1/2h(B+b) (for b) Area of trapezoid

3. Rose's garden is in the shape of a trapezoid. If the height of the trapezoid is 16m, one base is 20m and the area is 224m^2, find the length of the other base.

4. Yuri has a board that is 98 in long. He wishes to cut the board into two pieces so that one will be 10 in longer than the other. What should the length of each piece be?

5. The Randolphs used 12 more gallons of fuel in October than in September and twice as much fuel in November as in September. If they used 132 gallons for the 3 months, how much was used each month?

I don't know if it's just me or if these are really confusing but I cannot figure them out for the life of me. Please help and I will be forever grateful!! THANKS!!! :D