1)f(x)=4x+14x+1≤x+24x+1≤-2x+4x≤1/3 f(x)≤7/3最大值为7/3(2) f(x)=4x+1=x+2x+2≤4x+1x+2≤-2x+41/3≤x≤2/3f(x)≤8/3最大值为8/3(3)f(x)= -2x+4-2x+4≤4x+1-2x+4≤x+2x≥2/3f(x)=-2x+4≤8/3最大值为8/3∴f(x)最...