Ta có: \(\left|3x-5\right|\ge0\forall x\)
\(\left(2y+5\right)^{20}\ge0\forall y\)
\(\left(4z-3\right)^{206}\ge0\forall z\)
Do đó: \(\left|3x-5\right|+\left(2y+5\right)^{20}+\left(4z-3\right)^{206}\ge0\forall x,y,z\)
Dấu '=' xảy ra khi \(x=\dfrac{5}{3};y=-\dfrac{5}{2};z=\dfrac{3}{4}\)