speaking - writing

`1/3+2/3 .x=4/3`

`2/3 .x =1`

`x=3/2`

.

`3/5 x+1/4=1/10`

`3/5 x=-3/20`

`x=-1/4`

If this factory treated its waste well, there wouldn't be a lot of water pollution.

`cos^2α=16/49`

`sin^2α+cos^2α=1`

`<=>sin^2α+(4/7)^2=1`

`<=>sin^2α=33/49`

`4cos^2α-3sin^2α=4. 16/49 - 3. 33/49 = -5/7`

29. A

30. B

31. C

32. B

27. D
28. A
29. B
30. A

17. B -> was invented

18. A -> new stories

19, C -> to eat

1. B

1. D
2. D
3. A
4. B
5. A
6. if