Question

me ajudem por favor, preciso muito de ajuda

Answer 1

Explicação passo a passo:

Item a:

$3^x-5=4\\\\3^x=9\\\\3^x=3^2\\\\x=2\\\\S=\{2\}$

Item b:

$(\frac{1}{2})^{2x}=8\\\\(2^{-1})^{2x}=2^3\\\\2^{-2x}=2^3\\\\-2x=3\\\\x=-\frac{3}{2}\\\\S=\{-\frac{3}{2}\}$

Item c:

$8^x+20=20\\\\8^x=0\\\\S=\emptyset$

Item d:

$[(\frac{1}{5})^2]^x=\sqrt{\frac{1}{5}}\\\\(\frac{1}{5})^{2x}=(\frac{1}{5})^{\frac{1}{2}}\\\\2x=\frac{1}{2}\\\\x=\frac{1}{4}\\\\S=\{\frac{1}{4}\}$