Respuesta :

[tex]f(x)=4-4x\to y=4-4x\\\\4-4x=y\ \ \ |subtract\ 4\ from\ both\ sides\\-4x=y-4\ \ \ |divide\ both\ sides\ by\ (-4)\\x=-\dfrac{y}{4}+1\\\\subtitute\ y\in\{-20;-16;-8;\ 0;\ 4\}\\\\x=-\dfrac{-20}{4}+1=5+1=6\\\\x=-\dfrac{-16}{4}+1=4+1=5\\\\x=-\dfrac{-8}{4}+1=2+1=3\\\\x=-\dfrac{0}{4}+1=0+1=1\\\\x=-\dfrac{4}{4}+1=-1+1=0\\\\\Answer{\boxed{D=\{0;\ 1;\ 3;\ 5;\ 6\}}[/tex]