2. solution: let a be x, b be y and c be z, and according to the meaning of the question, we can get the ternary linear equations:

x+y+z=35 ①

2x=y+5 ②

( 1/3)y=( 1/2)z ③

To solve this system of equations, we must:

x= 10

y= 15

z= 10

A: These three numbers are 10, 15 and 10.

Exercise 8.4

1 、( 1)x = 2y =-3z = 1/2(2)x =-(3/4)y = 5/3z = 2

2 、( 1)x = 5y =-2z = 1/3(2)x =- 1y = 1/2z = 3

Let the three-digit number be x, the tenth digit number be y and the hundredth digit number be z.

Meaning, meaning: x+z=y

7z=x+y+2

x+y+z= 14

To solve this system of equations, x=5.

y=7

z=2

A: This three-digit number is 275.

4、x=30

y=20

z= 16

5. Solution: According to the meaning of the question, we can list the ternary linear equations:

-2=a+b+c

20=a-b+c

(9/4)a+(3/2)b+ c =( 1/9)a+( 1/3)b+ c

To understand this system of equations, we get: a=6.

b=- 1 1

c=3