29．已知f(x)=ex−1−e1−x+xf(x)=e^{x-1}-e^{1-x}+xf(x)=ex−1−e1−x+x，则不等式f(x)+f(6−3x)⩽2f(x)+f(6-3x)\leqslant 2f(x)+f(6−3x)⩽2的解集是___[2[2[2[，]+∞)+\infty )+∞)___．