1- B

2-C

3-C

4-C

Choose the best answer(A, B, C or D)

1. Today, subjects music and arts are put into the school __________ in VietNam.

A. so                             B. too                             c. either                             D.however

2. My cousin - Hoa, is the same age __________ me

A. as                             B. of                             C. to                             D.

3. For many pepple, a good knowledge of music and arts is regarded as a __________ for every stufent

A. need                             B. needs                             C. necessity                             D. necessary

4. This year's musical festival is not __________ it was last year

A. worse                             B. as good as                             C. as well as                             D. different from

5. Since the 1970, the festival in Glastonbury has taken __________ almost every year and has grown in size

A. time                             B. place                             C. note                             D. noe

Ta có:

^A-^B=18°

^B-^C=18°

=>^A-^B+^B-^C=18°+18°

=>^A-^C=36°

=>^C=^A-36°

Vì ^A-^B=18°

=>^B=^A-18°

Xét ΔABC có: ^A+^B^C=180°(đl tổng ba góc tam giác) 

=>^A+^A-18°+^A-36°=180°

=>3^A=234°

=>^A=78°

=>^B=78°-18°=60°

=>^C=78°-36°=42°

Từ  \(\frac{a+b-c}{c}=\frac{a-b+c}{b}=\frac{-a+b+c}{a}\)

\(\Rightarrow\frac{a+b-c}{c}+2=\frac{a-b+c}{b}+2=\frac{-a+b+c}{a}+2\)

\(\Rightarrow\frac{a+b+c}{c}=\frac{a+b+c}{b}=\frac{a+b+c}{a}\)

Nếu a + b + c = 0

=> a + b = - c

=> b + c = - a

=> c + a = - b

Khi đó \(\frac{\left(a+b\right).\left(b+c\right).\left(c+a\right)}{abc}=\frac{-a.\left(-b\right).\left(-c\right)}{abc}=-\frac{abc}{abc}=-1\)

Nếu \(a+b+c\ne0\)

\(\Rightarrow\frac{1}{c}=\frac{1}{b}=\frac{1}{a}\)

\(\Rightarrow a=b=c\)

Khi đó \(\frac{\left(a+b\right).\left(b+c\right).\left(c+a\right)}{abc}=\frac{2a.2b.2c}{abc}=\frac{8.abc}{abc}=8\)

Vậy nếu a + b + c = 0 thì \(\frac{\left(a+b\right).\left(b+c\right).\left(c+a\right)}{abc}=-1\) 

nếu a + b + c \(\ne\)0 thì  \(\frac{\left(a+b\right).\left(b+c\right).\left(c+a\right)}{abc}=8\) 

1. The hotel in New York was better than the hotel in California.

\(\rightarrow\)The hotel in the California wasn't as good as the hotel in New Year.

2. French is easier than German.

\(\rightarrow\)German isn't as easy as French

3. Rick is frienlier than Glenn.

\(\rightarrow\)Glenn isn't as friendly as Rick

4. Indonesia is hotter than VietNam.

\(\rightarrow\)Viet Nam isn't as hot as Indonesia

5. Football is more exciting than voleyball.

\(\rightarrow\)Volleyball isn't as exciting as football.

              ~ Hk tốt ~