⑴ 2t-t= 15

⑵ a-a*49%= 1020

⑶ b*80%- 10=70

⑷ (a-45000)÷30=200

2,

⑴

1/3-8x = 3- 1 1x/2

2-48x= 18-33x

-48x+33x= 18-2

- 15x= 16

x=- 16/ 15

⑵0.5x-0.7=6.5- 1.3x

0.5x+ 1.3x=6.5+0.7

1.8x=7.2

x=4

⑶ 1/6(3x-6)=2x/5-3

1/2(x-2)=2x/5-3

5(x-2)=4x-30

5x- 10=4x-30

x=-20

⑷( 1-2x)/3 =(3x+ 1)/7-3

7( 1-2x)=3(3x+ 1)-63

7- 14x=9x+3-63

- 14x-9x=-60-7

-23x=-67

x=67/23

⒊

x-(x- 1)/3=7-(x+3)/5

15x-5(x- 1)= 105-3(x+3)

15x-5x+5= 105-3x-9

10x+3x=96-5

13x=9 1

∴x=7