Câu 1: C

Câu 2: D

Câu 3: B

Câu 4; B

Câu 5: D

Câu 6: C

Câu 7: A

Câu 8: A

English was originally the language of England, but through the historical efforts of the British Empire it has become the primary or secondary language of many former British colonies such as the United States, Canada, Australia, and India. Currently, English is the primary language of not only countries actively touched by British imperialism, but also many business and cultural spheres dominated by those countries. It is the language of Hollywood and the language of international banking and business. As such, it is a useful and even necessary language to know. There are several factors that make the English language essential to communication in our current time. First of all, it is the most common foreign language. This means that two people who come from different countries (for example, a Mexican and a Swede) usually use English as a common language to communicate. That’s why everyone needs to learn the language in order to get in touch on an international level. Speaking it will help you communicate with people from countries all over the world, not just English-speaking ones.

My favorite subjects in school are math and science. Math is my favorite subject because it is fun. It is like a mystery to find the answer. It can be challenging and can take steps sometimes. I like science too because it is about discoveries. One reaction can create another reaction. If the people that are doing the experiment are not careful, they may get the wrong reaction.
Many different jobs use math and science. Science is used to find cures for people who are sick. Doctors and nurses use math to measure how much medicine to give to people. Salespeople need to know math to count money. Architects need to know math to design buildings. Pilots use these subjects to fly a plane. All of these people use math and science daily to measure, pay and count. Math and science are needed and used all around the world. That is why math and science are so important.

1) \(x-y=3\\ \Rightarrow\left(x-y\right)^2=3^2\\ \Rightarrow x^2-2xy+y^2=9\\ \Rightarrow\left(x^2+y^2\right)-2xy=9\\ \Rightarrow x^2+y^2=9+2xy\)

    \(\Rightarrow x^2+y^2=9-4\)(vì xy=-2)

    \(\Rightarrow x^2+y^2=5\)

2) \(x-y=3\\ \Rightarrow\left(x-y\right)^3=27\\ \Rightarrow x^3-3x^2y+3xy^2-y^3=27\\ \Rightarrow\left(x^3-y^3\right)+6x-6y=27\\ \Rightarrow\left(x^3-y^3\right)+6\left(x-y\right)=27\\ \Rightarrow\left(x^3-y^3\right)+18=27\\ \Rightarrow x^3-y^3=9\)

1: \(x^2+y^2=3^2-2\cdot\left(-2\right)=13\)

2: \(x^3-y^3=\left(x-y\right)^3+3xy\left(x-y\right)=3^3+3\cdot3\cdot\left(-2\right)=27-18=9\)

1 số chia hết cho 4 khi 2 chữ số tận cùng tạo thành số chia hết cho 4

34x5y chia hêt cho 4 =>5y chia hết cho 4 =>y thuộc {2;6}

Với y=2 thì 34x52 chia hết cho 9 =>3+4+x+5+2 chia hết cho 9 =>14+x chia hết cho 9 =>x=4

Với n=6 thì 34x56 chia hết cho 9 =>3+4+x+5+6 chia hết cho 9 =>18+x chia hết cho 9 =>x thuộc {0;9}

Ta có các số: 34452; 34056;34956

Để \(\overline{34x5y}\)chia hết cho 4 thì \(\overline{5y}\)chia hết cho 4 nên y sẽ bằng 2 hoặc 6.

+) Nếu y = 2 thì x = 4 , ta có số 34452
+) Nếu y = 6 thì x = 0 , ta có số 34056

Vậy ta tìm được 2 số thỏa mãn là 34452 và 34056

x=38 ; a=1; b=4

x = 38 còn a = 1 và b = 4

đây là toán lớp 6 thì hợp lí hơn

Gọi số đo của các góc A, B, C lần lượt là a;b;c (a;b;c > 0)

Vỉ các góc đó lần lượt tỉ lệ với các số 2;3;5 nên

\(\frac{a}{2}=\frac{b}{3}=\frac{c}{5}\) và a + b + c = 180^o

Áp dụng tính chất của dãy tỉ số = nhau ta có:

\(\frac{a}{2}=\frac{b}{3}=\frac{c}{5}=\frac{a+b+c}{2+3+5}=\frac{180^o}{10}=18^o\)

\(\Rightarrow\hept{\begin{cases}a=18^o.2=36^o\\b=18^o.3=54^o\\c=18^o.5=90^o\end{cases}}\)

Vậy góc A = 36^o; góc B = 54^o; góc C = 90^o

Festivals around the world : Lễ hội trên toàn thế giới .

Mk ko vt 1 đoạn văn để giúp bn đk mong bn thông cảm nhé .

# MissyGirl #