[tex]\displaystyle\bf\\d)\\\\(0,25)^4\cdot4^4=\\\\=\left(\frac{1}{4}\right)^4\cdot4^4=\\\\\\=\left(\frac{1}{4}\cdot4\right)^4=\left(\frac{4}{4}\right)^4=1^4=1[/tex]
