Ta có: 3x +3x+1+3x+2= 3x x 30 +3x x 31 +3x x 32=1053
Suy ra: 3x x(30+31+32)=3x x(1+3+9)=3x x 13=1053
Suy ra: 3x =1053:13=81
Mà 34 = 81
Vậy x = 4
tim x y thuoc z biet x mu 2 cong y nhan x cong y mu 2 bang x mu hai nhan y mu hai
3 mu x cong 2 cong 3 mu x bang 10
tim cac so nguyen x,y,z bt {5x-7} mu 2 cong {6 tru 5y } mu2 cong {5z } mu 2 bang 10
chứng minh ý a 8mu10 cong 2 mũ 20 chia hết cho41
chứng minh ý b 31 mu36 nhận 36 -313 mu 5 nhận 299 chia hết ch
chung minhý c 3 mu n công 3 cộng 2 mu n công 3 công 2 mu n công 2 công 2 mu n công 2 chia hết 6
chung minh y d d=2 cong 2 mu 2 cong 2mu 3 cong 2 mu 4 cong 2 mu 5 cong 2 mu 6 cong ....cong 2 mu 58 cong 2 mu 59 cong 2 mu 60 chia het cho 31
chung minh y e, e= 1cong 3 cong 3 mu 2 cong 3 mu 3 cong..cong 3 mu 98 cong 3 mu 99 chung minh e chia het cho5 chia het cho11
cmr A=1 cong 5 cong 5 mu 2 cong 5 mu 3 cong ....cong 5 mu 21 chia het cho 6
2 mu m cong 2 mu n bang 2 mu m cong n tim m va n
Chung minh nam cong nam mu hai cong nam mu ba cong nam mu 4 +...+nam mu chin cong nam mu muoi chia het cho sau
xin loi tai mk ko biet viet so mu nen moi nguoi co gang doc va giai gium.Mai mk thi toan hoc ki 1 roi
1) Tính:
a) A = 7 mu 2 phan 2 nhan 9 cong 7 mu 2 phan 9 nhan 16 cong 7 mu 2 phan 16 nhan 23 cong van van cong 7 mu 2 phan 65 nhan 72
