30．已知f(x)=3−2∣x∣f(x)=3-2\vert x\vertf(x)=3−2∣x∣，g(x)=x2−2xg(x)=x^{2}-2xg(x)=x2−2x，F(x)={g(x),f(x)⩾g(x),f(x),f(x)<g(x),F(x)=\left\{{\left.\begin{array}{l}{g(x),f(x)\geqslant g(x),}\\ {f(x),f(x)<g(x),}\end{array}\right.}\right.F(x)={g(x),f(x)⩾g(x),f(x),f(x)<g(x),，则F(x)(F(x)(F(x)( )))