Hello everyone, today I will talk about Mars, the 4th planet in our solar system. The name of Mars originally comes from the name of the Roman god of war and agriculture. It may not seem like these two things go together, but they do. Mars protected those who fought for their communities and stayed home to raise crops for food. Mars has two natural satellites, and their names are Phobos and Deimos. With a radius of 2,106 miles (3,390 kilometers), Mars is about half the size of Earth. The atmosphere of Mars is much thinner than Earth's. It contains more than 95% carbon dioxide and much less than 1% oxygen. Mar's temperatures are from -151°C to 20°C. Mars is colder than Earth. If you were to stand on the surface of Mars on the equator at noon, it would feel like spring at your feet and winter at your head. Mar's surface is rocky, with canyons, volcanoes, dry lake beds and craters all over it. It's called Red Planet because iron minerals in the Martian soil oxidize, or rust, causing the soil and atmosphere to look red. One day on Mars takes a little over 24 hours. Mars makes a complete orbit around the Sun in 687 days. Thanks for listening.

Hello everyone, today I will talk about Mars, the 4th planet in our solar system. The name of Mars originally comes from the name of the Roman god of war and agriculture. It may not seem like these two things go together, but they do. Mars protected those who fought for their communities and stayed home to raise crops for food. Mars has two natural satellites, and their names are Phobos and Deimos. With a radius of 2,106 miles (3,390 kilometers), Mars is about half the size of Earth. The atmosphere of Mars is much thinner than Earth's. It contains more than 95% carbon dioxide and much less than 1% oxygen. Mar's temperatures are from -151°C to 20°C. Mars is colder than Earth. If you were to stand on the surface of Mars on the equator at noon, it would feel like spring at your feet and winter at your head. Mar's surface is rocky, with canyons, volcanoes, dry lake beds and craters all over it. It's called Red Planet because iron minerals in the Martian soil oxidize, or rust, causing the soil and atmosphere to look red. One day on Mars takes a little over 24 hours. Mars makes a complete orbit around the Sun in 687 days. Thanks for listening.

a: \(\dfrac{16}{5}\cdot\dfrac{5}{6}-\left(\dfrac{3}{5}+\dfrac{1}{3}\right):2\)

\(=\dfrac{16}{6}-\dfrac{9+5}{15}:2\)

\(=\dfrac{8}{3}-\dfrac{14}{30}=\dfrac{8}{3}-\dfrac{7}{15}\)\(=\dfrac{40}{15}-\dfrac{7}{15}=\dfrac{33}{15}=\dfrac{11}{5}\)

b: \(\dfrac{7}{19}\cdot\dfrac{8}{11}+\dfrac{7}{19}:\dfrac{11}{3}+\dfrac{12}{19}\)

\(=\dfrac{7}{19}\cdot\dfrac{8}{11}+\dfrac{7}{19}\cdot\dfrac{3}{11}+\dfrac{12}{19}\)

\(=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)+\dfrac{12}{19}=\dfrac{7}{19}+\dfrac{12}{19}=\dfrac{19}{19}=1\)

c: \(\left(-\dfrac{2}{5}\right)^2+\dfrac{1}{2}\left(4,5-2\right)-25\%\)

\(=\dfrac{4}{25}+\dfrac{1}{2}\cdot2,5-0,25\)

\(=\dfrac{4}{25}+1,25-0,25=\dfrac{4}{25}+1=\dfrac{29}{25}\)

d: \(\left(2,07+3,005\right)-\left(12,005-4,23\right)\)

\(=2,07+3,005-12,005+4,23\)

=6,3-9

=-2,7

?

a) \(\dfrac{5}{3}=\dfrac{x}{9}\)

\(\Rightarrow x=\dfrac{5}{3}\cdot9\)

\(\Rightarrow x=15\)

Vậy x = 15.

b) Gọi số sách của hai lớp 7A và 7B lần lượt là \(a\), \(b\) (sách; \(a,b\in\mathbb{N}^*\))

Vì số sách của hai lớp 7A và 7B tỉ lệ thuận với số học sinh của mỗi lớp, mà số học sinh hai lớp lần lượt là 32 và 36 nên: \(\dfrac{a}{32}=\dfrac{b}{36}\)

Vì lớp 7A quyên góp được ít hơn lớp 7B 8 quyển sách nên: \(b-a=8\) (1)

Áp dụng tính chất của dãy tỉ số bằng nhau và (1), ta được:

\(\dfrac{a}{32}=\dfrac{b}{36}=\dfrac{b-a}{36-32}=\dfrac{8}{4}=2\)

\(\Rightarrow\left\{{}\begin{matrix}a=2\cdot32=64\left(tm\right)\\b=2\cdot36=72\left(tm\right)\end{matrix}\right.\)

Vậy lớp 7A và lớp 7B quyên góp được số sách lần lượt là 64 quyển sách và 72 quyển sách.

\(Toru\)

The weather's been sunny all the time!  The food is both cheap and delicious.  Everyone here is friendly and hospitable.  Yesterday we visited the Citadel and took a trip along the Huong River.  Tomorrow we're off to see the Khai Dinh and Tu Duc Temples.  Wish you were here!  Love, Nick.

1The weather's been sunny all the time!

2 The food is both cheap and delicious. 3

3people is friendly and hospitable.

4 Yesterday we visited the Citadel and went on a trip along the Huong River.

5 Tomorrow we will visit Khai Dinh and Tu Duc Temples. 

Tổng độ dài hai đáy ban đầu là 36+52=88(m)

Tổng độ dài hai đáy lúc sau là 88+4=92(m)

Chiều cao của mảnh vườn là \(90:\left(\dfrac{99}{2}-\dfrac{88}{2}\right)=90:\dfrac{4}{2}=90:2=45\left(m\right)\)

Diện tích mảnh vườn là 88x45/2=1980(m²)

Mảnh vườn hình gì vậy em?

a: Xét ΔMAB và ΔMEC có

MA=ME

\(\widehat{AMB}=\widehat{EMC}\)(hai góc đối đỉnh)

MB=MC

Do đó: ΔMAB=ΔMEC

=>\(\widehat{MAB}=\widehat{MEC}\)

mà hai góc này là hai góc ở vị trí so le trong

nên AB//CE

\(x\) + 20,09 = 40,1

\(x\)             = 40,1 - 20,09

\(x\)            = 20,01

30,5 - \(x\) = 9,05

           \(x\) = 30,5 - 9,05

          \(x\)  = 21,45