ta có
9000=32x1000=23x103
32x23x53
=32x22x52
(3x2x5)2=900
Đ/S...
ta có
9000=32x1000=23x103
32x23x53
=32x22x52
(3x2x5)2=900
Đ/S...
Cmr n^2+n+1 khòg la so chinh phuong vs n la so tu nhien lon hon 0
cho (n*(n+1)*(n+2)):6 la tong cua n so chinh phuong dau tien. khi do tong cua 10 so chinh phuong dau tien
tim mot so chinh phuong co 4 chu so vua la so chinh vua la so lap phuong
tim mot so chinh phuong co 4 chu so biet so gom 2 chu so dau lon hon so gom 2 chu so sau la 1 don vi
cho a la 1 so chinh phuong co 4 chu so biet 2 chu so dau va 2 chu so cuoi cua giong nhau hoi a la bao nhieu
chung minh rang tich cua 4 so tu nhien lien tiep cong voi 1 la mot so chinh phuong
chung to rang tong cua n so chan khac 0 khong phai la so chinh phuong
tim x,y de thoa man
a) n^2-4xy+7 la so chinh phuong
b) n^2-3n-1 la so chinh phuong
cho a,b la cac so nguyen thoa man
2018a2-20192=a-b
chung minh gia tri tuyet doi cua a-b la so chinh phuong