Cho ab+bc+ac=1,a,b,c thuoc Q CMR:A=(a^2+1)(b^2+1)(c^2+1) la binh phuong cua 1 so huu ti
Cho x y z la cac so huu ti doi mot khac nhau va khac khong thoa man x+1/y=y+1/z=z+1/x Chung minh xyz=1 hoac xyz=-1
Cho x,y la các số hữu tỉ khac 0 thỏa mãn x5+y5=2*x3*y3 chung minh A= 1-1/x*y la binh phuong cua mot so huu ti
cho x,y,z thuoc Q va doi mot khac nhau. cmr 1/ (x-y)^2+1/(y-z)^2+1/(z-x)^2 la binh phuong cua 1 so huu ti
cho cac so nguyen duong a,b,c thoa man :(a,b,c)=1;ab=c(a+b).Cm a+b la so chinh phuong
cho tam giac abc vuong tai a co so do do dai canh huyen bc la so huu ti .ve phia ngoai tam giac dung hinh chu nhat bcde sao cho cd = bc/\(\sqrt{2}\) . goi m va n theo thu tu la giao diem cua ad , ae voi bc . chung minh \(\sqrt{bm^2+cn^2}\) la so huu ti
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
giai ho minh voi minh can gap lam ai tra loi minh tich cho
1 tim cac so nguyen x thoa man 1 trong cac dieu kien sau
a) 2x+1 la scp
b) 4x=1 la scp
c)8x+1 la scp
2 tim nguyen tu nhien cua phuong trinh x^2-y^2=y+1
biet x,y,m,n la cac so nguyen thoa man: x+y=m+n. chung minh S=x^2+y^2+m^2+n^2 luon =bang cac binh phuong cua 3 so nguyen