Two points can be connected into 1 line segment, three points can be connected into three line segments, and four points can be connected into six line segments, so it is inferred that eight points can be connected into (28) line segments, and 12 points can be connected into more line segments than eight points (38).

Teacher Li deposited 50,000 yuan in the bank and chose lump-sum deposit and withdrawal for two years, with an annual interest rate of 4.4%. At maturity, she can get interest of (4,400) yuan (excluding interest tax) and principal and interest of * * * (5.44) million yuan.

The sum of two adjacent natural numbers is x, which is expressed by letter formula: ① the average value of these two natural numbers is (x÷2), ② the smaller natural number is ((x- 1)÷2).

17 minutes, you can ask questions if you don't understand, and make sure you are all right!