Respuesta :
Answer:
[tex]3^2=x+5[/tex]
Step-by-step explanation:
Given equation:
[tex]\log_3(x+5)=2[/tex]
Method 1
[tex]\textsf{Using the Log law:} \quad \log_ab=c \:\: \Longleftrightarrow \:\: a^c=b[/tex]
[tex]\implies \log_3(x+5)=2[/tex]
[tex]\implies 3^2=x+5[/tex]
Method 2
Make both sides of the equation the index to base 3:
[tex]\implies \log_3(x+5)=2[/tex]
[tex]\implies 3^{\log_3(x+5)}=3^2[/tex]
Apply the log law [tex]a^{\log_ax}=x[/tex] :
[tex]\implies x+5=3^2[/tex]
Swap sides:
[tex]\implies 3^2=x+5[/tex]
Solve for x
Although the question hasn't asked to solve for x, here is the solution:
[tex]\implies 3^2=x+5[/tex]
[tex]\implies 9=x+5[/tex]
[tex]\implies x=9-5[/tex]
[tex]\implies x=4[/tex]
Check
Substitute the found value of x into the original equation:
[tex]x=4 \implies \log_3(4+5)=\log_39=2 \quad \leftarrow\textsf{correct}[/tex]
[tex]\\ \rm\Rrightarrow log_3(x+5)=2[/tex]
- log_a^b=c then b=a^c
[tex]\\ \rm\Rrightarrow x+5=3^2[/tex]
[tex]\\ \rm\Rrightarrow x+5=9[/tex]
[tex]\\ \rm\Rrightarrow x=9-5[/tex]
[tex]\\ \rm\Rrightarrow x=4[/tex]