Posted by **Peter** on Friday, January 20, 2012 at 1:54am.

solve 3^x=4^(x-2)

- Maths -
**Reiny**, Friday, January 20, 2012 at 9:59am
take ln of both sides

ln (3^x) = ln (4^(x-2))

x(ln3) = (x-2)(ln4)

= x(ln4) - 2ln4

xln3 - xln4 = -2ln4

x(ln3 - ln4) = -2ln4

x = -2ln4/(ln3-ln4)

or

x = 2ln4/(ln4 - ln3)

if get appr. 9.638

check:

3^9.638 = appr. 39672.63

4^7.638 = 39676.6

----- close enough using only 3 decimals, if I use my calculator's memory and store the full value of x, my error is 5.9x10^-6

## Answer This Question

## Related Questions

- maths - 1.solve the set of linear equation by matrix method.a+3b+2c=3,2a-b-3c=-8...
- Maths - Hey :) I'm sitting my maths non-calculator GCSE tomorrow and am ...
- Maths - solve the following pair of simultaneous equation: (x/a)+(y/b)=1 (x/b)+(...
- maths - Solve the set of linear equations by the matrix method : a+3b+2c=3 , 2a...
- maths - y varies partly as the square root of x when x=9 and y=3. Write the ...
- maths - A survey o 85 students asked them about the subjects they liked to study...
- maths - helo sir/madam can u help me to solve this problem solve the following ...
- maths - how do i solve this equation? 2/(x+1)=1/(x-1) - (1/(2x-1)) thx Get a ...
- Maths - I must come up with an maths model to solve this... Sally is baking some...
- maths - solve this equation;5t(6 times 10 neg.3)=(6 times10neg -2) does it look ...

More Related Questions