b) 917-(417-65)

= 917- 352

= 565

c) 31-[26-(2017+35)]

=  31-[26-2052]

= 31- (-2026)= 31+2026= 2057

g) -418-{-218-[-118-(-131)]+2017}

= -418-{-218-[-118+131]+2017}

= -418-{-218-13+2017}

= -418-1786

= -2204

Các câu còn lại thì bạn làm tương tự nha!( nhân chia trước, cộng trừ sau, trong ngoặc làm trước ngoài ngoặc làm sau)

16, a

17, a

18, d

19, a

20, b

21, c

17 B: (động vật hoang dã)

19 A:(khí hậu mưa)

20 B(bị động và expect+to-v)

21 C(động lực)

1D 2A 3C 4B 5D 6B

Bài 1:

a, \(\dfrac{2}{3}\) + \(\dfrac{1}{5}\). \(\dfrac{10}{7}\)

= \(\dfrac{2}{3}\) + \(\dfrac{2}{7}\) 

= \(\dfrac{20}{21}\)

b, \(\dfrac{7}{12}\) - \(\dfrac{27}{7}\). \(\dfrac{1}{18}\)

= \(\dfrac{7}{12}\) - \(\dfrac{3}{14}\)

= \(\dfrac{31}{84}\)

c, \(\dfrac{3}{10}\). \(\dfrac{-5}{6}\) - \(\dfrac{1}{8}\)

= - \(\dfrac{1}{4}\) - \(\dfrac{1}{8}\)

= - \(\dfrac{3}{8}\)

d, - \(\dfrac{4}{9}\): \(\dfrac{8}{3}\) + \(\dfrac{1}{18}\)

= - \(\dfrac{1}{6}\) + \(\dfrac{1}{18}\)

= - \(\dfrac{1}{9}\)

e,  {[(\(\dfrac{1}{2}\) - \(\dfrac{2}{3}\))² : 2 ] - 1}. \(\dfrac{4}{5}\)

= {[ (-\(\dfrac{1}{6}\))² : 2] - 1}. \(\dfrac{4}{5}\)

= { [\(\dfrac{1}{36}\) : 2] - 1}. \(\dfrac{4}{5}\)

= { \(\dfrac{1}{72}\) - 1}. \(\dfrac{4}{5}\)

=- \(\dfrac{71}{72}\).\(\dfrac{4}{5}\)

= -\(\dfrac{71}{90}\)

4 careful

5 boring

6 good

7 young

8 amazing

9 unimportant

10 toothache

11 natural

12 homeless

13 enjoyment

II

1 old

2 learn

3 another

4 when

5 over

6 of

7 wear

8 home

9 write

10 visited

1 I used to say up late to watch football matches last year

bạn ơi mình phần đầu mình cần giải thích tại sao. điền mấy từ trong ngoặc á giúp mik vs

III. 

A. 

1. B

2. C

3. B

4. A

5. D

B. 

1. C

2. B

3. B

4. A

5. C

1 b c b a d

2 c b b a c nha

Đề dài thế này sao giải thích nhanh cho e đc

Part 1

1 C

2 B

3 D

4 C

5 B

6 A

Part 2

1 T

2 F

3 F

4 F

V

1 That old house has just been bought

2 If he doesn't take these pills, he won't be better

3 I suggest taking a train

4 Spending the weekend in the countryside is very wonderful

nhiều thật đấy

1 correct

2 success => only success

3 was released => released

4 correct

5 focused on => on

6 as a => a

7 correct

8 each others => others

9 satisfy with => satisfy

10 correct

11 correct

\(a^3+b^3+c^3=3abc\)

=>\(\left(a+b\right)^3+c^3-3ab\left(a+b\right)-3abc=0\)

=>\(\left(a+b+c\right)\left[\left(a+b\right)^2-c\left(a+b\right)+c^2\right]-3ab\left(a+b+c\right)=0\)

=>\(\left(a+b+c\right)\left(a^2+2ab+b^2-ac-bc+c^2-3ab\right)=0\)

=>\(a^2+b^2+c^2-ab-ac-bc=0\)

=>\(2a^2+2b^2+2c^2-2ab-2ac-2bc=0\)

=>\(\left(a^2-2ba+b^2\right)+\left(b^2-2cb+c^2\right)+\left(a^2-2ac+c^2\right)=0\)

=>\(\left(a-b\right)^2+\left(b-c\right)^2+\left(a-c\right)^2=0\)

=>\(\left\{{}\begin{matrix}a-b=0\\b-c=0\\a-c=0\end{matrix}\right.\Leftrightarrow a=b=c\)

\(A=\dfrac{a^{2023}}{b^{2023}}+\dfrac{b^{2023}}{c^{2023}}+\dfrac{c^{2023}}{a^{2023}}\)

\(=\dfrac{a^{2023}}{a^{2023}}+\dfrac{b^{2023}}{b^{2023}}+\dfrac{c^{2023}}{c^{2023}}\)

=1+1+1

=3