Question

If log 3 to the base 30=a and log 5 to the base 30=b,then find log 8  to the base 30 URGENT PLZ answer fast

Answer 1

$log_{30}8$ = $log_{30} 2^{3}$ = 3 $log_{30} 2$
                                 = 3 $log_{30} 30/15)$
                                 = 3 $log_{30} (30/15)$
                                 = 3 ( $log_{30} 30$ - $log_{30} 15$ )
                                 = 3 ( $log_{30} 30$ - $log_{30} 5$  - $log_{30} 3$ )
                                 = 3( 1 - b - a )
                                 

Answer 2

log 8 to the base 30 =log 2 cube to the base 30 =3log 2 to the base 30 =3log30/15 to the base 30 =3(log 30 the base 30 - log15 to the base 30)=3(log30 to the base 30 -log 5 to the base 30 - log3 to the base 30)= 3(1-a-b)