logarithms???????

3 ⤊

how do you solve for x?

5^x=4^x+3

2007-12-18 18:47:06 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

3 answers

Do you mean 4^(x+3)? If so, then take ln of both sides and use that ln(a^b) = b ln(a) for any a > 0 and any b.

2007-12-18 18:52:21 · answer #1 · answered by a²+b²=c² 4 · 1⤊ 0⤋

Assuming that you mean:-
5^x = 4^(x + 3)
x log 5 = (x + 3) log 4
x log 5 = x log 4 + 3 log 4
x (log 5 - log 4) = 3 log 4
x = 3 log 4 / (log 5 - log 4)
x = 3 log 4 / log (5/4)
x = 18.6

Note
log can be to any base.

2007-12-19 04:37:45 · answer #2 · answered by Como 7 · 2⤊ 0⤋

about 1.47318179

2007-12-19 04:14:48 · answer #3 · answered by sothanaphan 2 · 0⤊ 0⤋