The problem of shifting term of linear equation of one variable (review) will be done tonight.

One (1)-7-3 = 4x-2x (2) 9x+12x-2x =-4-3+9 (3) 25x-4x =12+5.

23x/2-1=1-(x+5)/6 on the shore is multiplied by 6 to get 9x-6=x+5, and the shift term 9x-x=5+6.

8x = 1 1x = 1 1/8。

Three17x-14 =1-2x+12

7x-2x= 13+ 14

5x=27

x=27/5

A (x-1) =1-a (x+1) simplification

ax-a= 1-ax+a

2ax=2a+ 1

Replace 2ax=2a+ 1 with x=27/5.

54a/5=2a+ 1

54a/5-2a= 1

54a- 10a=5

44a=5

a=5/44

2 (1) Let the actual payment amount be F.

When adopting the scheme of buy one get one free, F=250+5(x- 10).

When converting by 9, F=0.9(250+5x).

(2) When the charges are the same, 250+5(x- 10)=0.9(250+5x).

200+5x=225+4.5x

5x-4.5x=225-200

0.5x=25

x=50

So when x=50, the charges of the two preferential ways are the same.

Friend! Take it! I am your best friend!