log (8x-1)/(5x+7) =2
2006-12-06 04:08:47 · 6 answers · asked by mathhelp2008 1 in Science & Mathematics ➔ Mathematics
put both sides up as an exponent:
(8x-1)/(5x+7) = 10² (assuming you're using base 10 log)
---> 8x-1 = 100 * (5x+7) and you can ride this one into the sunset.
2006-12-06 04:13:03 · answer #1 · answered by Anonymous · 0⤊ 0⤋
there is a formula, the log with base a of b = c so that you can transform it with the definition of logatirthm a^c=bthe answers would be 10^2=(8x-1)/(5x+7)
x=-1.42
2006-12-06 04:14:50 · answer #2 · answered by photojenny 2 · 0⤊ 0⤋
log (8x-1)/(5x+7) =2
I assume you are using natural logs
Then e^ln((8x-1)/(5x+7))= e^2
(8x-1)/(5x+7) = e^2
8x-1= (5x + 7)e^2 = 5xe^2 +7e^2
8x - 5xe^2 = 7e^2+1
x(8-5e^2) = 7e^2 +1
x = (7e^2 +1)/(8-5e^2)
If you are using common logarithms (base 10), then
10 ^log((8x-1)/5x+7))= 10^2 = 100
Then (8x-1)/(5x+7)) = 100
500x +700 = 8x-1
492x = -701
x = -701/492 approximately = - 1.423
2006-12-06 04:53:04 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋
8x-1=10x+14
8x=10x+13
-13=2x
x= -13/2
x= -6.5
2006-12-06 04:14:07 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Here's a hint log(x/y) = log(x) - log(y)
2006-12-06 04:11:16 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Who is your teacher and what school do you go to? You are in trouble.
2006-12-06 04:12:26 · answer #6 · answered by Brett C 1 · 0⤊ 0⤋