12. Solve the following equation:

1.x=7

2.x=3.5

13. Solve the following equation:

1.x= 6/7

2.x=-3

14. Complete the following equation and indicate the basis of this step in brackets:

Solve the equation: ——

Solution: (denominator is removed), and we get: 2 (2x+1)-(10x+1) = 6 (property 2 of the equation).

Without parentheses, we get: 4x+2- 10x- 1=6.

(Transfer and merger), get: -6x=5.

When the coefficient is converted into 1, it is: x=- 5/6 (property 2 of the equation).

15. if the solution of the equation about x: one sixth *(x-2)=a- one third *(x- 1) is x= 1, find the value of a.

Solution: Substitute x= 1 into the equation:

One sixth *( 1+2)=a- one third *( 1- 1)

One sixth *3=a

A= half

∴a= half

16. It is known that the solution of equation 2- 1/3 *(a-x)=2x about x is x= 1. Find the solution of the equation a(y-5)-2=a(2y+3) about Y.

Solution: substitute x= 1 into ①.

Get a= 1

Substitute a= 1 into ②.

6 1 page

First, take a look and choose.

D、C、D、B .

Second, think about it and fill it out.

(5)3

(6) 12、 14、 16

(7) 3168km

(8)2 1

(9)-8

Third, try to answer.

10. Solve the following equation:

1.x=- 12

2.x= 16/5

Get y=- 10.