cho 26 so nguyen,trong do tong cua 5 so bat ki la mot so nguyen duong.chung to rang tong cua 26 so nguyen da ch la mot so nguyen duong.
cho 16 so nguyen trong do tich cua 3 o bat ky luon la mot so nguyen am. chung to rang tich cua 16 so nguyen do la mot so nguyen duong
minh can gap!
Cho 61 so nguyen .Hoi tong cua 61 so nguyen do la so nhu the nao neu :
a,Tong cua 6 so bat ki trong chung la mot so nguyen am
b, tong cua 6 so bat ki trong chung la mot so nguyen duong
a. cho 2017so nguyen trong do 7 so bat ki luon co tong am. hoi tong cua2017 so do la am hay duong?
b. cho 2017 so nguyen trong do 7 so bat ki luon co tich am. hoi tich cua 2017 so do la am hay duong? moi so nguyen do la am hay duong
cho 25 so nguyen trong do tich cua 3 so nguyen bat ki la mot so nguyen duong chung minh rang tat ca 25 so nguyen da cho deu la so nguyen duong
Cho 31 so nguyen trong do co 5 so bat ki co tong la so nguyen duong.Hay chung to rang tong cua 31 so do deu la so nguyen duong
cho 2014 so nguyen trong do tich cua 3 so bat ky luon la 1 so nguyen am chung to rang tich cua 2014 so nguyen do la 1 so nguyen duong
giá trị tuyệt đối của một số nguyên a co the la: A.so nguyen duong,so nguyen am b.so nguyen duong,so 0, c.so nguyen duong,so nguyen am hoac so 0
cho 20 so nguyen a1,a2,a3,...,a20 khac 0 thoa man ,a1>0 va tong cua 3 so lien nhau bat ki la so duong va tong 20 so da cho la so am chung minh rang a1*a14+a12*a14<a1*a12