Cho 2 đường thẳng MN , PQ cắt nhau tại O tạo thành bốn góc khác góc bẹt biết NÔP=2/3MÔP . Tính số đo mỗi góc tạo thành
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
TT
3
XO
31 tháng 7 2020
Ta có : (a + b + c) \(⋮\)2
=> \(\left(a+b+c\right)^2⋮2\)
=> \(\left(a+b+c\right)\left(a+b+c\right)⋮2\)
=> \(\left(a+b+c\right).a+\left(a+b+c\right).b+\left(a+b+c\right).c\)
=> \(a^2+ab+ac+ab+b^2+bc+ac+bc+c^2\)
=> \(a^2+b^2+c^2+2\left(ab+bc+ca\right)⋮2\)
Vì \(2\left(ab+bc+ca\right)⋮2\)
=> \(a^2+b^2+c^2⋮2\left(\text{đpcm}\right)\)
31 tháng 7 2020
Bài làm:
Ta có: Vì a+b+c chia hết cho 2
=> a+b+c chẵn
Nên ta xét các TH sau:
+Nếu: Cả 3 số a,b,c đều chẵn
=> a2,b2,c2 đều chẵn
=> a2+b2+c2 chia hết cho 2
+Nếu: Chỉ có 1 số trong 3 số a,b,c chẵn
G/s a là số chẵn, b và c là 2 số lẻ
=> a2 chẵn và b2,c2 lẻ
=> a2+b2+c2 chẵn
=> đpcm
31 tháng 7 2020
1.Complete with be going to.
1.Kelly...is going to have...a party for her birthday.(have)
2.Mike and Sarah............aren't comming.........................with us.(not/come)
3.When........................are you tidying........................your room?(you/tidy)
4.Mr and Mrs Allan............are moving.........................to Canada.(move)
5............Is your brother selling............................his car?(your borther/sell)
6.I..........amnot lending...............Ben my camera.(not lend)
7.We...........are staying...............at home on Sunday.(stay)
8.I..................amnot telling..............Anna about the party.(not/tell)
XO
31 tháng 7 2020
1.Kelly...is going to have...a party for her birthday.(have)
2.Mike and Sarah......are not going to come...............................with us.(not/come)
3.When....are .you..going to tidy.........................................your room?(you/tidy)
4.Mr and Mrs Allan..........are going to move...........................to Canada.(move)
5......When is your brother going to sell..................................his car?(your borther/sell)
6.I......am not going to lend..................Ben my camera.(not lend)
7.We...are going to stay.......................at home on Sunday.(stay)
8.I.....am not going to tell...........................Anna about the party.(not/tell)
28 tháng 8 2020
1. Unless we try to save them, our sources of energy will soon end.
2. Mike doesn't play chess as well as Barbare.
3. Although the story's silly, many people enjoyed the film.
4. The ket price was high, however; many people went to see that film.
5. Despite the fact that he's young, he performs very well.
6. In spite of being a comedy, i didn't find it funny at all.
7. The film was so boring, but Jack saw it from beginning to end.
8. Although the film has a happy ending, it begins with a terrible disaster.
9. Despite the fact that the film was a bit frightening, i really enjoyed it.
10. In spite of being young, he performs very well.
11. No river in the world is longer than the Nile.
12. We might visit Japan in the future.
13.My brother is a fast runner.
14.Nga's favourite sport is badminton.
A
3 tháng 8 2020
1, Unless we try to save them, our soures of energy will soon end.
2, Mike doesn't play chess as well as Barbare.
3, Although the story was silly, many people enjoyed the film.
4, The ket price was high; however, many people went to see that film.
5, Despite his young age, he performs very well.
6, In spite of the fact that it was a comedy, i didn't find it funny at all.
7, The film was so boring, but Jack saw it from beginning to end.
8, Although the film has a happy ending, it begins with a terrible disaster.
9, Despite a bit frightening film, i really enjoyed it.
10, In spite of his young age, he performs very well.
11, No river in the world is longer than the Nile river.
12, We might visit Japanese in the future.
13, My father is a fast runner.
14, Nga's favourite sport is badminton.
15, If we don't protect the environment, we will destroy ourselves.
16, If she isn't more hard-working, she will get low marks.
17, If he doesn't listen to his parents, he will fail.
KN
31 tháng 7 2020
\(\left|x-3\right|=\left|-3\right|\)
\(\Rightarrow\left|x-3\right|=3\)
\(\Rightarrow\orbr{\begin{cases}x-3=3\\x-3=-3\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=6\\x=0\end{cases}}\)
31 tháng 7 2020
Bài làm:
Ta có: \(x.x^3=81\)
\(\Leftrightarrow x^4=81=3^4\)
\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=-3\end{cases}}\)
HL
4
31 tháng 7 2020
Bài làm:
Ta có: \(\left(x+9\right)+\left(x+10\right)+\left(x+11\right)+...+\left(x+18\right)=235\)
\(\Leftrightarrow\left(x+x+...+x\right)+\left(9+10+...+18\right)=235\)
\(\Leftrightarrow10x+\frac{\left(9+18\right).10}{2}=235\)
\(\Leftrightarrow10x+135=235\)
\(\Leftrightarrow10x=100\)
\(\Rightarrow x=10\)
Vậy x = 10
TT
31 tháng 7 2020
g = 9
\(\left(x+9\right)+\left(x+10\right)+\left(x+11\right)+...+\left(x+18\right)=235\)
\(\Leftrightarrow\left(x+x+x+...+x\right)+\left(9+10+11+...+18\right)=235\)
\(\Leftrightarrow\left(x+x+x+...+x\right)+\frac{\left(18+9\right)\times\left[\left(18-9\right):1+1\right]}{2}=235\)
\(\Leftrightarrow10x+135=235\)
\(\Leftrightarrow10x=100\)
\(\Leftrightarrow x=100:10=10\)