Question

I NEED HELP ASAP!!!!!! WILL GIVE BRAINLIEST IF ANSWER IS CORRECT

Answer 1

So, the one you picked is correct because:
$2^{a-3} = b-4$
$log_2(b-4) = a-3$
$log_2(b-4) +3 = a$

This eliminates the second option because there is only 1 possible value for a. 

The 4th option is also correct because it's saying:
$log_2(b-4) = a-3$

Now, just by pure logic, you can tell that to solve for b, you have to use option 3 because Option 5 has already been used to solve for a.

So, your answers are: #1, #3, and #4.