chung to rang:n;3n+2 va 14n+9 la 2 so nguyen to cung nhau
chung minh rang:n.(n+8).(n+13)chia het cho 3 voi n thuoc so tu nhien
chung minh rang:n.(n+8).(n+13)chia het cho 3 voi n thuoc so tu nhien.
n la so tu nhien chung minh rang:n.(n+1).(2n+1)chia het cho 2,3
VII. Rearrange the sentences to make meaningful sentences
Question 6:cake/ Lang Lieu/ was/ Chung/ Day/ to/ the/ first/ cake/ one/ make
A. Lang Lieu was the first one to make Chung cake and Day cake.
B. Lang Lieu was the first make one to Chung cake and Day cake.
C. Lang Lieu was the one cake and to first make Chung Day cake.
D. Lang Lieu was first one to make the Chung cake and Day cake
Question 7: Vietnamese/ found/ watermelon/ think/ a/ that/ prince/ Mai An Tiem/ named.
A. Vietnamese found that a prince named Mai An Tiem think watermelon.
B. Vietnamese think that prince a named Mai An Tiem found watermelon.
C. Vietnamese think watermelon that a prince named Mai An Tiem found.
D. Vietnamese think that a prince named Mai An Tiem found watermelon.
Question 8: I/ story/ will/ that/ meaningful/ never/ forget
A. I never will forget that meaningful story. B. I will never that forget meaningful story.
C. I will never forget that meaningful story. D. I will forget never that meaningful story.
Question 9:: I/ believe/ in/ don’t/ ghost/ stories.
A. I don’t believe in ghost stories. B. I don’t in believe ghost stories.
C. I don’t believe ghost in stories. D. I believe don’t in ghost stories.
Question 10: What/ the/ story/ most/ is/ for/ exciting/ you?
A. What is exciting the most story for you? B. What is story the most exciting for you?
C. What is the most exciting story for you? D. What is the for you most exciting story?
VII. Rearrange the sentences to make meaningful sentences
Question 6:cake/ Lang Lieu/ was/ Chung/ Day/ to/ the/ first/ cake/ one/ make
A. Lang Lieu was the first one to make Chung cake and Day cake.
B. Lang Lieu was the first make one to Chung cake and Day cake.
C. Lang Lieu was the one cake and to first make Chung Day cake.
D. Lang Lieu was first one to make the Chung cake and Day cake
Question 7: Vietnamese/ found/ watermelon/ think/ a/ that/ prince/ Mai An Tiem/ named.
A. Vietnamese found that a prince named Mai An Tiem think watermelon.
B. Vietnamese think that prince a named Mai An Tiem found watermelon.
C. Vietnamese think watermelon that a prince named Mai An Tiem found.
D. Vietnamese think that a prince named Mai An Tiem found watermelon.
Question 8: I/ story/ will/ that/ meaningful/ never/ forget
A. I never will forget that meaningful story. B. I will never that forget meaningful story.
C. I will never forget that meaningful story. D. I will forget never that meaningful story.
Question 9:: I/ believe/ in/ don’t/ ghost/ stories.
A. I don’t believe in ghost stories. B. I don’t in believe ghost stories.
C. I don’t believe ghost in stories. D. I believe don’t in ghost stories.
Question 10: What/ the/ story/ most/ is/ for/ exciting/ you?
A. What is exciting the most story for you? B. What is story the most exciting for you?
C. What is the most exciting story for you? D. What is the for you most exciting story?
6-D
7-A
8-C
9-A
10-C
theo minh la the chuc ban hoc tot ^^
bai 1 : chung to rang ababab la boi chung cua ab
b, chung to rang ababab chia het cho 3 va 10101
Ta co : ababab=ab0000+ab00+ab
=ab.10000+ab.100+ab.1
=ab.(10000+100+1)
=ab.10101
Co :10101 chia het cho 3
Nen ab.10101 chia het cho 3
Vay suy ra ababab la boi cua 3
**** nhe
a chung to rang aaa chia het cho 37
b chung to rang aaaaaa chia het 37
a) Ta co : aaa = a x 111
vì 111 chia hết cho 37 =>a x 111 chia hết cho 37 hay aaa chia hết cho 37
b) Ta có aaaaaa = a x 111111
vi 111111 chia hết cho 37 => a x 111111 chia hết cho 37 hay aaaaaa chia hết cho 37
Dieu phai chung minh
gọi A =n ^2+n+1(nEN). chung to A ko chia het cho 2.chung to A ko chia het cho 5
A=n(n+1)+1
Vì n(n+1) chia hết cho 2
nên A=n(n+1)+1 không chia hết cho 2
Chung minh rang trong 3 so nguyen to lon hon 3 luon co 2 so nguyen to ma tong hoac hieu cua chung chia het cho 12
B1 : chung to rang ( 8n+6 ) ( 5n+7 ) chia het cho 2
B2: chung to rang : 1090 chia hết cho 2 và 3