how do i solve for x on this problem log3x + log3(2x-3) = 3 , but the 1st two 3's are in sub-script. any help is appreciated, thanks.
log3x + log3(2x-3) = 3
log3(x(2x - 3)) = 3 raise both sides 3^
x(2x - 3) = 27
2x^2 - 3x - 27 = 0
(x + 3)(2x - 9) = 0
x = -3 (impossible to have negative log so no!!!)
or x =9/2 (this is the answer!)
Logs are to base 3 :-
log x + log (2x - 3) = 3
log [ x (2x - 3) ] = 3
x (2x - 3) = 3³
2x² - 3x = 27
2x² - 3x - 27 = 0
(2x - 9)(x + 3) = 0
x = 9/2 , x = - 3
Accept x = 9/2
put the right hand side into log base 3, ie. log3 27
combine left hand side: log3 x + log3 (2x-3), giving u log3 [x(2x-3)]
comparing left side and right side, x(2x-3) = 27
solve for quadratic equation 2x^2 - 3x - 27 = 0 and find x
:)
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Verified answer
log3x + log3(2x-3) = 3
log3(x(2x - 3)) = 3 raise both sides 3^
x(2x - 3) = 27
2x^2 - 3x - 27 = 0
(x + 3)(2x - 9) = 0
x = -3 (impossible to have negative log so no!!!)
or x =9/2 (this is the answer!)
Logs are to base 3 :-
log x + log (2x - 3) = 3
log [ x (2x - 3) ] = 3
x (2x - 3) = 3³
2x² - 3x = 27
2x² - 3x - 27 = 0
(2x - 9)(x + 3) = 0
x = 9/2 , x = - 3
Accept x = 9/2
put the right hand side into log base 3, ie. log3 27
combine left hand side: log3 x + log3 (2x-3), giving u log3 [x(2x-3)]
comparing left side and right side, x(2x-3) = 27
solve for quadratic equation 2x^2 - 3x - 27 = 0 and find x
:)