c, (2x-1)⁶ = (2x-1)⁸ <=> (2x-1)⁶ - (2x-1)⁸ <=> (2x-1)⁶ . [1-(2x-1)²] = 0

<=> (2x-1)⁶ . [(1-2x+1) . (1+2x-1)] = 0 <=> (2x-1)⁶ . [(2-2x) . 2x] = 0

Có:

* (2x-1)⁶ = 0 <=> 2x-1=0 <=> x=\(\dfrac{1}{2}\)

* 2-2x=0 <=> 2x=2 <=> x=1

* 2x=0 <=> x=0 <=> x=0

b, (x-1)⁵ = -32 => -32 = (-2)⁵ <=> x-1 = -2 <=> x = -1

a, (2x-4)⁴ = 81 => 81 = 3⁴ <=>2x-4 = 3 <=> 2x = 4+3 = 7 <=> x = \(\dfrac{7}{2}\)

1.c

2.b

3.d

4.màu sắc của các màu diệp lục

I've more finished the book.

Marry’s watch is far more expensive than mine.

He speaks English much more rapidly than he does Korean.

I need to get two more tickets.

Their job allows them less freedom than ours.

31. advantage

32. money

33. helping

34. how

35. because

36. subscribed / provided

37. school

38. free

39. community

40. provided