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 a,b,c, la cac so duong thoa man a+b+c=1, c/m :1/a+1/b+1/c>=9
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 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 cac so duong a,b,c thoa man : ab+a+b=3
tim GTNN cua bieu thuc C=a^2+b^2
Cho a,b,c la cac so nguyen duong thoa man: abc=1. CMR
\(\frac{1}{a^3\left(b+c\right)}+\frac{1}{b^3\left(c+a\right)}+\frac{1}{c^3\left(a+b\right)}\ge\frac{3}{2}\)
cho cac so duong a,b,c thoa man (a^2+b^2+c^2)^2>2*(a^4+b^4+c^4)
cm rang a,b,c la do dai ba canh cua tam giac.
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 cac so thuc duong thoa man a+b+c=3.cmr:
(a2+ab2/b2+a+b)+(b2+bc2/c2+b+c)+(c2+ca2/a2+c+a) lon hon hoac bang 2
