Tuyển Cộng tác viên Hoc24 nhiệm kì 26 tại đây: https://forms.gle/dK3zGK3LHFrgvTkJ6
cho n so nguyen bat ki :a1;a2;a3;...;an chung to rang S=|a1-a2|+|a2-a3|+...+|an-a1| la 1 so chan
cho a la mot so tu nhien le, b la mot so tu nhien bat ki
chung minh rang : hai so a va a.b + 4 la hai so nguyen to cung nhau
cho n so nguyen bat ki :a thu 1, athu 2,...a thu n. Chung to rang tong S=|a thu 1-a thu 2|+|a thu 2 -a thu 3| +...+|a thu n-1-a thu n|+|a thu n-a thu 1| la mot so chan
(giai ra nhe)
cho n la so tu nhien bat ki ;chung minh rang (n+3) va(2n+5) la 2 so nguyen to cung nhau
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
a, Chung minh rang 5m+3 va 3m+2 la 2 so nguyen biet rang 1 so bang 10 ngen to cung nhau voi m la so nguyen to bat ky.
b,Tim 1 bo ba so nguyen to biet rang 1 so bang 10 phan tram tong cua 3 so can tim
Ai lam nhanh nhat minh tick cho
Cho 25 so nguyen, trong do tich cua 3 so bat ki la 1 so duong. C/ to rang tich cua 25 so do la 1 so duong
Cho 2014 so nguyen, trong do tich cua 3 so bat ki luon la 1 so nguyen am.chung to rang tich cua 2014 so nguyen do la mot so nguyen duong
Ai nhanh minh tick luon
cho 31 so nguyen trong do tong cua 5 so bat ki la 1 so duong . chung minh rang tong cua 31 so do la so duong
