Resposta:
Explicação passo-a-passo:
1)
[tex]16^{\sqrt{2^8}}=x^{\sqrt{2^4}}\\\\=\:16^{2^{\frac{8}{2}}}\:=\:x^{2^{\frac{4}{2}}}\\\\=\:16^{2^4}\:=\:x^{2^2}\\\\=\:16^{16}\:=\:x^4\\\\x=4[/tex]
2)
[tex]25^2\sqrt{2^3}\\\\=25^2\cdot \:2^{\frac{3}{2}}\\\\=25^2\cdot \:2\sqrt{2}\\\\=625\cdot \:2\sqrt{2}\\\\=1250\sqrt{2}[/tex]
3)
[tex]\sqrt[3]{8^2}\\\\=\left(8^2\right)^{\frac{1}{3}}\\\\=8^{\frac{2}{3}}\\\\=\left(2^3\right)^{\frac{2}{3}}\\\\=2^2\\\\=4[/tex]
4)
[tex]20\sqrt{2}+10\sqrt{8}\\\\=20\sqrt{2}+10\sqrt{2^{3} }\\\\=20\sqrt{2}+20\sqrt{2}\\\\=40\sqrt{2}[/tex]
5) (-5)² - √16
= 25 - 4
= 21
