i have a math question?

Question

if lnx+ln(x-6)=ln5x then x= ?

i dont know how to get rid of the ln to simplify it, and the books examples didnt help =( thanks for ur time

Answer 1

Hi Dear;
You need to simplify this,so you will see how easy it could be;
lnx+ln(x-6)=ln5x
as you know
ln(a) + ln(b) = ln(ab)
so, ln(x) + ln(x-6) =
ln(x^2-6x) = ln(5x)

Step 1;
Remove ' ln ' from both sides; so we have
x^2 - 6x = 5x
x^2 - 6x -5x = 0
x^2 -11x = 0
Factor 'x' ;
x ( x - 11) = 0

x = 0
OR
x - 11 = 0 ; x = 11

Good Luck....

Answer 2

1

Answer 3

ln (logarithm) has the property: ln(x . y) = ln(x) + ln(y) [x and y not null]
Here: ln(x) + ln(x-6) = ln (5x)
=> x (x-6) = 5x [x not null, x-6 not null]
=> x (x-11) = 0 [x not null, x-6 not null
=> x = 11 (x=0 is not a solution coz x not null, coz remember the formula contains ln(x) and ln (0) not defined)

Answer 4

---- means divide

lnx+ln(x-6)=ln5x
---- -------- -----
ln ln ln

x+x-6=5x
2x-6=5x
-2x -2x
-6=3x
--- ---
3 3
-2=x

Answer 5

The ln a + ln b = ln (a+b), so ln x + ln(x-6) = ln x(x-6)

Does that help?

Answer 6

we know that ln(a) + ln(b) = ln(ab)

so, ln(x) + ln(x-6) = ln(x^2-6x) = ln(5x)

hence x^2-6x = 5x or x^2 = 11x hence x=0 or x=11

Answer 7

i have a math problem also...... i don't do too good in math either. so i can't help you here.

maybe ask John Madden.