\(\dfrac{\left(-\dfrac{5}{7}\right)^{n+1}}{\left(-\dfrac{5}{7}\right)^n}=\left(-\dfrac{5}{7}\right)^{n+1}:\left(-\dfrac{5}{7}\right)^n\\ =\left(-\dfrac{5}{7}\right)\)

Ta có:\(\dfrac{x}{-2}=\dfrac{y}{4}\)

Áp dụng tích chất của dãy tỉ số bằng nhau, ta có:

\(\dfrac{x}{-2}=\dfrac{y}{4}=\dfrac{x-y}{-2-4}=\dfrac{8}{3}\\ \Rightarrow x=\dfrac{8}{3}.\left(-2\right)=\dfrac{-16}{3};y=\dfrac{8}{3}.4=\dfrac{32}{3}\)

Vay

a,Ta có;

\(1=\left(m+2009\right).\left(-1\right)+\left|-1\right|\\ \Leftrightarrow-m-2009+1=1\\ \Leftrightarrow-m=2009\\ \Leftrightarrow m=-2009\)

\(\dfrac{2x+3}{5x+2}=\dfrac{4x+5}{10x+2}\\ \Leftrightarrow\dfrac{4x+6}{10x+4}=\dfrac{4x+5}{10x+2}\)

Áp dụng t.c của dãy tỉ số bằng nhau, ta có:

\(\dfrac{4x+6}{10x+4}=\dfrac{4x+5}{10x+2}=\dfrac{4x+6-4x-5}{10x+4-10x-2}=\dfrac{1}{2}\)

=>\(4x+6=\dfrac{1}{2}\left(10x+4\right)\)

=>4x+6=5x+2

=>x=6-2=4

Vậy x=4

Among many subjects student learns in school, I like math the most. This is one of the compulsory subjects from primary to high school ad even university. Math teaches learner about numbers and operation. Being good at math brings us several advantages. Doing math exercise improves one’s brain and its brainstorm. Moreover, people learning math can think more logically and make up one mind. There are many subjects we can apply mathematics to solve the problem: economics, engineering and even business. Math is said to originate from ancient Greece and develop completely as today. In VN it’s an increasing number of mathematical genius such as Ngo Bao Chau. Therefore, Vietnamese are very proud of it. In my opinion, every student should be good at math or at least learn it. Since human gain lots of achievement related to math, specifically in modern society.

1.My sister is not ______ as her sister

A. So old B. Old C. Older D. More old

2. Your penalcase is _______ as mine

A. Cheap B. As cheap C. So cheap D. Cheaper

3. Vung Tau is not _____ as Nha Trang

A. Beautiful B. So beautiful C. More beautiful D. The same beautiful

4. I am ______ as Sam

A. As young B. So younger C. Younger D. A và C

5. Girls are _______ as boys

A. Less intelligent B. Intelligent C. More intelligent D. as intelligent

6. Your bag is different ________ her bag

A. So B. For C. From D. In

7. I like English music , and so ___

A. I do B. Don't C. I don't D. Do I

8. My friend draws many beautiful pictures . He is a _____

A. Teacher B. Farmer C. Painter D. Singer

9. David is my favourite singer . He _______ very well

A. Sings B. Plays C. Draws D. Takes

10. He plays ______ in a band

A. Photo B. Singer C. Music D. The guitar

\(a,x^2-113=31\\ \Leftrightarrow x^2=144\\ \Leftrightarrow x=\pm12\\ Vay...\\ b,\sqrt{x+2,29}=2.3\\ \Leftrightarrow x+2,29=6^2\\ x=36-2,29=33,71\\ c,x^4=256\\ \Leftrightarrow x=\pm4\\ Vay...\\ d,\left(\sqrt{x}-1\right)^2=0,5625\\ \Leftrightarrow\sqrt{x}-1\in\left\{-0,75;0,75\right\}\\ \Leftrightarrow\sqrt{x}\in\left\{0,25;1,75\right\}\\ Vay...\\ e,2\sqrt{x}-x=0\\ \Leftrightarrow\sqrt{x}\left(2-\sqrt{x}\right)=0\\ \Leftrightarrow\sqrt{x}=0hoac2-\sqrt{x}=0\\ \Leftrightarrow x=0hoacx=4\\ f,x+\sqrt{x}=0\\ \Leftrightarrow\sqrt{x}\left(\sqrt{x}+1\right)=0\\ \Leftrightarrow x=0hoacx=1\)

Ăn nem,thịt tái,...có gây nhiễm sán lá gan

Vì nem và thịt tái đều những thực phảm chưa được đun nấu chín nên vi khuẩn, sán chưa chết hết .Do đó có khả năng nem, thịt tái,... còn sán lá

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