cho n điểm phân biệt (n thuộc N,n>2 hoặc =2).Vẽ các đoạn thẳng đi qua các cặp điểm.Có bao nhiêu đoạn thẳng đc tạo thành?
HELP ME PLEASE!!!!!😣😣😣😣😣😣😣😣😣😣
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Khách
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TI
Hãy cho biết điểm A(3;9) có thuộc đồ thị hàm số y=3x không? Vì sao?
Mn giúp mọi với nhé!!!!😣😣😣😣😣😣😣😣😣😣
1
NH
27 tháng 12 2019
Có nha.
Giả sử điểm A thuộc đồ thị hàm số đã cho, ta có: x=3, y=9
Thay x=3, y=9 vào hàm số y=3x,ta có: 9=3.3
=>Điều giả sử đúng =>A thuộc đò thị hàm số y=3x.
DM
3
O
13 tháng 8 2017
Chien and I stuied in the same secondary class. He was a little overwieght and not quite tall, however, his outlook with bright complexion and crew hair was appealing. frankly, at first he hadn’t left any impression on me, but, once we were set to sit together, i found him a interesting and jovial person.Moreover, he was very active, it appeared that if he didn’t take part in the class activity, the things wouldn’t have run smoothly. Yet, Chien’s studying was not good, therefore, wherever he asked me anything about the lesson, i awlays tried my best to explain it to him. On the other hand, thanks to Chien, i learnt many fascinating games, or good amusement places after the class. what a pity that we no longer studied in the same school. My family moved to another city, we scacrely meeteach other. however, we still keep in touch and we are always best friend.
26 tháng 9 2017
Among my friends, I cherish the most is Ha.She is a good student of my class, she lived with her parents in a small house near my house. She has long black hair, oval face and eyes speak. What particularly struck me about her was the smile. She looks so cute when he smiles. She is a form of friends that I can share everything. She always believed and helped me in every situation. She is friendly, gentle and endearing all friends. She likes Literacy, reading, listening to music and go under heaven mua.Chung I have a lot in common with each other, has become good friends over the past 5 years. Although time has passed long in any case, I'm and Ha also trying to keep this friendship
16 tháng 9 2017
(x+1)+(x+2)+(x+3).........(x+1000)
=x+1+x+2+...+x+1000
=1000x+(1+2+3+...+1000)
=1000x+(1000-1+1).(1000+1):2=500500+1000x
1 tháng 7 2019
a) \(-5x+\frac{1}{2}=\frac{2}{3}\\ -5x=\frac{2}{3}-\frac{1}{2}\\ -5x=\frac{1}{6}\\ x=\frac{1}{6}:\left(-5\right)\\ x=\frac{-1}{30}\)Vậy \(x=\frac{-1}{30}\)
b) \(\frac{1}{-5}-\frac{2}{3}+1\frac{1}{2}x=\frac{1}{2}\\ \frac{-13}{15}+\frac{3}{2}x=\frac{1}{2}\\ \frac{3}{2}x=\frac{1}{2}-\frac{-13}{15}\\ \frac{3}{2}x=\frac{41}{30}\\ x=\frac{41}{30}:\frac{3}{2}\\ x=\frac{41}{45}\)Vậy \(x=\frac{41}{45}\)
c) \(2\left(\frac{1}{4}-3x\right)=\frac{1}{5}-4x\\ \frac{1}{2}-6x=\frac{1}{5}-4x\\ \frac{1}{2}-\frac{1}{5}=6x-4x\\ \frac{3}{10}=2x\\ x=\frac{3}{10}:2\\ x=\frac{3}{20}\)Vậy \(x=\frac{3}{20}\)
d) \(\frac{-5}{2}-3\left(\frac{1}{3}-x\right)=\frac{1}{4}-7x\\ \frac{-5}{2}-1+3x=\frac{1}{4}-7x\\ \frac{-7}{2}+3x=\frac{1}{4}-7x\\ 7x+3x=\frac{1}{4}+\frac{7}{2}\\ 10x=\frac{15}{4}\\ x=\frac{15}{4}:10\\ x=\frac{3}{8}\)Vậy \(x=\frac{3}{8}\)
V
5
2 tháng 1 2018
Among my friends, I cherish the most is Ha.She is a good student of my class, she lived with her parents in a small house near my house. She has long black hair, oval face and eyes speak. What particularly struck me about her was the smile. She looks so cute when he smiles. She is a form of friends that I can share everything. She always believed and helped me in every situation. She is friendly, gentle and endearing all friends. She likes Literacy, reading, listening to music and go under heaven mua.Chung I have a lot in common with each other, has become good friends over the past 5 years. Although time has passed long in any case, I'm and Ha also trying to keep this friendship
2 tháng 1 2018
Chien and I stuied in the same secondary class. He was a little overwieght and not quite tall, however, his outlook with bright complexion and crew hair was appealing. frankly, at first he hadn’t left any impression on me, but, once we were set to sit together, i found him a interesting and jovial person.Moreover, he was very active, it appeared that if he didn’t take part in the class activity, the things wouldn’t have run smoothly. Yet, Chien’s studying was not good, therefore, wherever he asked me anything about the lesson, i awlays tried my best to explain it to him. On the other hand, thanks to Chien, i learnt many fascinating games, or good amusement places after the class. what a pity that we no longer studied in the same school. My family moved to another city, we scacrely meeteach other. however, we still keep in touch and we are always best friend.
MN
0
PA
17 tháng 7 2017
\(\dfrac{1+3\sqrt{2}-2\sqrt{3}}{\sqrt{6}+\sqrt{3}+\sqrt{2}}\)
\(=\dfrac{\left[1+\sqrt{6}\left(\sqrt{3}-\sqrt{2}\right)\right]\left[\sqrt{6}-\left(\sqrt{3}+\sqrt{2}\right)\right]}{\left[\sqrt{6}+\left(\sqrt{3}+\sqrt{2}\right)\right]\left[\sqrt{6}-\left(\sqrt{3}+\sqrt{2}\right)\right]}\)
Tử:
\(\left[1+\sqrt{6}\left(\sqrt{3}-\sqrt{2}\right)\right]\left[\sqrt{6}-\left(\sqrt{3}+\sqrt{2}\right)\right]\)
\(=\sqrt{6}-\left(\sqrt{3}+\sqrt{2}\right)+6\left(\sqrt{3}-\sqrt{2}\right)-\sqrt{6}\) (nhân phân phối)
\(=5\sqrt{3}-7\sqrt{2}\)
Mẫu:
\(\left[\sqrt{6}+\left(\sqrt{3}+\sqrt{2}\right)\right]\left[\sqrt{6}-\left(\sqrt{3}+\sqrt{2}\right)\right]\)
\(=6-\left(5+2\sqrt{6}\right)\)
\(=1-2\sqrt{6}\)
Ta có:
\(\dfrac{5\sqrt{3}-7\sqrt{2}}{1-2\sqrt{6}}\)
\(=\dfrac{\left(5\sqrt{3}-7\sqrt{2}\right)\left(1+2\sqrt{6}\right)}{1-24}\)
\(=\dfrac{5\sqrt{3}+30\sqrt{2}-7\sqrt{2}-28\sqrt{3}}{-23}\)
\(=\dfrac{-23\left(\sqrt{3}-\sqrt{2}\right)}{-23}\)
\(=\sqrt{3}-\sqrt{2}\)
Số đoạn tạo thành : 1+2+3+...+(n-3)+(n-2)+(n-1)