a: Xét ΔADC có

E là trung điểm của AD

K là trung điểm của AC

Do đó: EK là đường trung bình của ΔADC

Suy ra: EK//DC và \(EK=\dfrac{CD}{2}\)

Xét ΔCAB có

K là trung điểm của AC
F là trung điểm của BC

Do đó: KF là đường trung bình của ΔCAB

Suy ra: KF//AB và \(KF=\dfrac{AB}{2}\)

1: \(a^2-4b^2=\left(a-2b\right)\left(a+2b\right)\)

2: \(16a^2-b^4=\left(4a-b^2\right)\left(4a+b^2\right)\)

3: \(4a^4-81b^4=\left(2a^2-9b^2\right)\left(2a^2+9b^2\right)\)

Bài 1:

góc M=góc A=42 độ

góc N=180-42-54=84 độ

Bài 2
AB+BC=8cm

MN-NP=2cm

=>AB-BC=2cm

mà AB+BC=8cm

nên AB=5cm; BC=3cm

=>MN=AB=5cm; NP=BC=3cm; AC=MP=6cm

\(X+X:0,5=27\)

\(\Rightarrow X\left(1+\dfrac{1}{0,5}\right)=27\)

\(\Rightarrow X\left(1+2\right)=27\)

\(\Rightarrow3X=27\Rightarrow X=27:3=9\)

bằng 9 nhaa

9

Chủ đề gì nhii?

The 21st century was a century of science and cone -monks. Therefore, the demand for Gie one of the forms but now, some young people are abusing video games,

As we know, video games are very popular in Vietnam, and Tini countries have advanced to produce electronics when in recent years, they go to work, the number of participants also play is also Not small. Not only in urban areas, although it is the current quota, from adults to young children, male or female because so popular, but the number of curiosity, tu tu and the attractiveness of c GRE GAME WEEKS AUTHER NOT NOT HEALTE OF THE PEOPLE'S PEOPLE'S IN THE GAME, so I continued to play with the time of the action r, causing the situation of the game in the youth. Recently, it has been a number of friends who do not have enough money to play games, CNN made very regrettable mistakes.

As a result, many of you have a number of diseases such as nearsightedness, kimh miraculous disorders, which are the result of weakening learning due to abundant time for games. That not only does it cause trouble with parents and th, but the most warning is the phenomenon

The theft only heals once or twice. Over time, also familiar with the bad nature of their people. The second largest consequence of the video game is leading to many social evils. But we have many modern games that are in the world, but because of the conflict when playing or talking, the two enemies boil the chewing head; That confrontation from a good, gentle person, when the whole ham was not to confirm that it was a lung. The third consequence is also concerned that it is impossible

So where is the phenomenon of the above phenomenon? We do not deny that the electronic world is where that player is the purpose that the soft producers when the video game is attractive by ordinary images, the software manufacturer or the plot select the plot. of comic books, legends, the response of the player will be great. The second Nguyn Nhan is the imagination of the player will be stimulated. But in a game, they will become a brave bank to eliminate and destroy violence as a game today. Also, it is a number of reviews, so for the purpose of all, many people despite the time of the past, sitting hard to stick their eyes on the screen H when they want to play video games is not really,

The phenomena that are not above are also due to the responsibility of parents on many parents who lack the care of their parents and the friends.

in-every nhé

in-at

in his/at the

15×2121/4343+15×222222/434343
= 15 x (21x101)/(101x43) + 15x(22x 10101)/(43x10101)
= 15 x 21/43 + 15 x 22/43
= 15x(21/43 + 22/43)
= 15x1 = 15

=15 nha

Đáp án 15

1. There aren’t any pencils on the table. Do you have any pencil?

TK: -Gia đình em thường sử dụng phương pháp chế biến thực phẩm có sử dụng nhiệt: chiên ( rán ), luộc, kho, xào.