① Solving equation: x/2.5 = 8028 * a can be written as (8a) or (A8); (3) comics, story books each 9.5 yuan, 8.5 yuan; It costs (9.5a+8.5b) yuan to buy a comic book and a story book; ④ The side length of a square plate is 1 decimeter, the perimeter is (4a) decimeter, and the area is. ⑤ Naughty family spends N yuan on water and electricity in February, and his family spends (n÷28) yuan on water and electricity this month. There are m apple trees in the orchard, twice as many as peach trees, and (2m) peach trees. Liu Xing is one year old, so she was (a-3) years old three years ago.

That's all, nothing!