1.3B 4D 5A 6B 7D 8D 9C 10C

Two.

1.2.88 times 10 cubic 2.1:9 3.9 4.15.1/4 6.4380.

17 problem: 3 18 problem: x is less than 2.

2 1 question: 1 22 question: y 1 equals negative x points; 12 y2 equals minus two thirds x2 S=6.

Question 23: (1)4 people (2) one third.

Question 24: (1) Root number 2

Question 25: (1)y 1 equals 20x plus 540 y2 equals 10x+630 (2) The maximum value in April is 4.5 million yuan.

(3)a= 10

Question 26: (1)t= 1 (2) I can't say that there are four relationships, and their values are between 0 and 1 to 1 to 33 and 44 to 6 respectively.

(3)t 1 = 2t 2 = 4t 3 = 3- radical 3 t4=3+ radical 3.