## Annetta_Martin 2 years ago Help with Logarithms?

1. Annetta_Martin

2. Best_Mathematician

|dw:1365375002492:dw|

3. Annetta_Martin

For #4 this is how I did it....

4. Annetta_Martin

(x - 2) log(7) = x * log(5) x * log(7) - x * log(5) = 2 log(7) x [log(7) - log(5)] = 2 log(7) x [log(7) - log(5)] = 2 log(7) x = 2 log(7) / [log(7) - log(5)] = log(49) / log(7/5) ≈ 11.57

5. Annetta_Martin

#2 *

6. HawkCrimson

looks gud :)

7. Annetta_Martin

For #1 this is how I have done it so far...

8. Annetta_Martin

16^x-4 = 3^3-x (x-4)log16 = (3-x)log3 xlog16 - 4log16 = 3log3 - xlog3 xlog16 + x log3 = 3log3 + 4log16 x = (3log3 + 4log16) / (log16 + log3)

9. HawkCrimson

wats the problem?

10. HawkCrimson

it looks fine too :)

11. Annetta_Martin

I don't know how to finish it though... :(

12. Annetta_Martin

I feel like I got stuck and I don't know where to go from there.

13. HawkCrimson

cannt u type it all into ur calculator now and solve?

14. Annetta_Martin

I don't have those types of calculators, it was my teacher that tried helping me out with the first one.

15. HawkCrimson

u need a calculator to do logs..

16. HawkCrimson

i have one though and i can tell u wat the answer is :)

17. HawkCrimson

x = (3log3 + 4log16) / (log16 + log3) x = 3.72