Question

Me ajuda com o mmc dessa equação exponencial

Answer 1

Resposta:

$7^{x} +\frac{7^{x} }{7} +\frac{7^{x} }{7^{2} }+\frac{7^{x} }{7^{3} } =400\\\\7^{x} (1+\frac{1}{7} +\frac{1}{7^{2} } +\frac{1}{7^{3} })= 400\\\\7^{x} (\frac{7^{3} +7^{2}+7^{1}+1}{7^{3} } )= 400\\\\\\7^{x} (\frac{343 +49+7+1}{343 } )= 400\\\\\\\\7^{x} (\frac{400}{343 } )= 400\\\\\\\\7^{x} = \frac{400}{\frac{400}{343} } \\\\7^{x} =343\\\\7^{x} =7^{3}\\ \\x=3$

Answer 2

Resposta:

7^(x)* (1+ 1/7  +1/7²+1/7³) =400

7^(x)* (7³+ 7²  +7+1)/7³ =400

7^(x)* (343+ 49  +7+1) =400 *7³

7^(x)* (400) =400 *7³

7^(x) =7³

x=3