Answer:
Explanation:
The trick is knowing the link between logarithmic functions and exponential functions.
if you have an exponential function like this b^x = a you can turn it into a logarithmic function log_b(a) = x. You say it log base b of a equals x. As you can tell this form is useful for solving for the exponent if it is a variable. I'll give an example.
2^x = 8
I made it easy, you could just try a few values for x and you'd be able to tell x = 3 THis also means log_2(8) = 3
One more thing to mention, if the "base" number is e that is a special kind of log called the natural log, which you can write as ln(x). so basically ln(x) = log_e(x) (log base e of x).
Now, we can deal with your problems.
ln(x) = 9 Remember ln is log base e
log_e(x) = 9 And also remember log_b(a)=x can be written as b^x=a
e^9 = x
e^4 = y is just that in reverse.
log_e(y) = 4
ln(y) = 4
If you ever get it in the form log_e your teachers are going to want you to convert it to ln, so keep that in mind to.