Solve the equation:
log 3x = log 5 + log (x-4)
I understand that I must condense Log 5 + log (x-4);however, what do I do with the other side of the equation, log 3x?
2006-11-29 17:49:49 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
log 3x = log 5 + log (x-4)
log 3x = log 5(x-4)
10 ^ (log 3x) = 10 ^ (log 5(x-4))
3x = 5(x-4)
3x = 5x - 20
-2x = -20
x = 10
Answer checks out.
2006-11-29 17:53:57 · answer #1 · answered by Michael M 6 · 0⤊ 0⤋
log 3x = log 5 + log (x-4)
log 3x = log 5(x-4)
by comparison
log 3x = log 5(x-4)
3x = 5(x-4)
3x = 5x - 20
-2x = -20
x = 10
2006-11-30 01:59:15 · answer #2 · answered by csp 2 · 0⤊ 0⤋
putting everythin as exponent of e gives :
3x = e^(log5 + log(x-4)) => 3x = (x-4)*5 .etc etc
used : e^(a+b) = e^a * e^b, e^log5 = 5
2006-11-30 02:04:19 · answer #3 · answered by gjmb1960 7 · 0⤊ 0⤋