Sagot :
[tex]D:x-12>0\\
D:x>12\\
\log_3(x-12)=\log_35+2\log_33\\
\log_3(x-12)=\log_35+\log_33^2\\
\log_3(x-12)=\log_35+\log_39\\
\log_3(x-12)=\log_3(9\cdot5)\\
\log_3(x-12)=\log_345\\
x-12=45\\
\boxed{x=57}
[/tex]
2log 3 = log 3^2 = log 9 ;
log 5 + 2log 3 = log 5 + log 9 = log( 5 * 9 ) = log 45 ;
log ( x - 12 ) = log 45;
x - 12 = 45 ;
x = 12 + 45 ;
x = 57 ;
But, x - 12 > 0;
And, 57 - 12 > 0 ;
The solution is 57 .
log 5 + 2log 3 = log 5 + log 9 = log( 5 * 9 ) = log 45 ;
log ( x - 12 ) = log 45;
x - 12 = 45 ;
x = 12 + 45 ;
x = 57 ;
But, x - 12 > 0;
And, 57 - 12 > 0 ;
The solution is 57 .