3^n+2-2^n+2+3^n-2^n
=3^n+2+3^n-(2^n+2+2^n)
=3^n(3^2+1)-2^n(2^2+1)
=3^n.10-2^n.5=3^n.10-2^n-1.10=10(3^n-2^n-1) chia hết cho 10(đpcm)
chung minh rang : voi moi so nguyen duong n thi :3n+2 -2n+2 +3n -2n chia het cho 10
chung minh rang: 3n+2 -2n+2 +3n -3n chia het cho 10 voi moi n nguyen duong
chung minh rang voi moi so nguyen duong n thi
10n + 18n -1 chia het cho 27
Chung minh rang: Voi moi so nguyen duong n thi: 3n+2 - 2n+2 + 3n - 2n chia het cho 10
GIUP MIK VS MOI NGUOI OI!
CMR voi moi so nguyen duong n thi B=3^n+2 -2^n+2 +3^n -2^n chia het cho 10
chung minh rang voi moi n nguyen duong ta luon co
4^n+3+4^n+2-4^n+1-4^nchia het cho 300
Bai 1: chung minh rang: voi moi so nguyen duong n thi:
\(3^{n+2}-2^{n+2}+3^n-2^n\)chia het cho 10
Bai 2: Chung to rang:
A=75.(4\(^{2004}\)+4\(^{2003}\)+....+4\(^2\)+4+1)+25 la so chia het cho 100
Bai 3: Chung minh rang 3a + 2b :17 [=] 10a +b :17 (a,b thuoc Z)
b, Cho da thuc f(x) =ax\(^2\)+ bx+c 9a,b,c nguyen)
CMR nếu f(x) chia hết cho 3 với mọi giá trị của x thì a,b,c đều chia hết cho 3 ?
Mau giup minh voi
CMR : \(3^{n+2}-2^{n+4}+3^n+2^2\)chia het cho 30 voi moi n nguyen duong
chung minh rang moi n nguyen huong ta luon co
4^n+3+4^n+2-4^n+1-4^n chia het cho 300