cho a,b,c,d la cac so nguyen duong doi 1 khac nhau thoa man a/a+b + b/b+c + c/c+d + d/d+a =2
CMR abcd la 1 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
do vui:co a;b;c thoa man ab+bc+ac=1.cmr(a^+1)(b^+1)(c^+1) la 1 so chinh phuong
co cac so nguyen duong a,b.c nguyen to cung nhau tm (a+b)=ab cmr a+b la co chinh phuong
cho a,b,c, la cac so duong thoa man a+b+c=1, c/m :1/a+1/b+1/c>=9
cho a,b,c la cac so duong thoa man (1/a+1/b+1/c)>=(a+b+c), chung minh a+b+c>=3abc
cho so nguyen to p va cac so duong x,y thoa man 4x^2-3xy-y^2-p(3x+2y)=2p^2 CHUNG MINH RANG 5x-1 la so chinh phuong
Cho cac so nguyen duong a b c thoa man
(a+1)^3+(b+2)^3+(c+3)^3=3(a+1)(b+2)(c+3)
Cho a,b,c la cac so nguyen duong thoa man: abc=1. CMR
\(\frac{1}{a^3\left(b+c\right)}+\frac{1}{b^3\left(c+a\right)}+\frac{1}{c^3\left(a+b\right)}\ge\frac{3}{2}\)