Tìm \(a,b\in N\) thỏa mãn \(ab=2\left(a+b\right)\)

Tìm a, b thỏa mãn :

\(\frac{a^2+1}{a-1}.\frac{b^2+1}{b-1}=\frac{1}{2}\left(ab+1\right)\)

\(x^3+2\sqrt{\left(3x-2\right)^3}=3x\left(3x-2\right)\)

\(\text{Cho }a,b,c>0\text{ thỏa mãn }a+b+c=3\)

\(\text{CMR: }\frac{1+b}{1+4a^2}+\frac{1+c}{1+4b^2}+\frac{1+a}{1+4c^2}\ge\frac{6}{5}\)