Question

If n = 8 and 16 · 2m = 4n – 8, then m = ?

Answer 1

Substitute n=8 into the equation;

16*2m = 4*8-8 which gives
32m = 24 then divide both sides by 32
m=3/4

Answer 2

I don't understand.

Answer 3

16.2m=4n-8
32m=4n-8
therefore n=8
by putting the value of n in above equation:
32m=4(8)-8
32m=32-8
32m=24
m=24/32
m=6/8
or m=3/4

Answer 4

Which part is confusing you?

Answer 5

The part where you substitute n. how is it not an exponent anymore?

Answer 6

Where does it say that it's an exponent?
Does the question say 4 to the power of n?

Answer 7

yeah. oh crap. the question is messed up here. it didn't paste properly.

Answer 8

if n = 8 and 16 * 2^m = 4^ (n-8), them m = ?

Answer 9

i'm sorry about that.

Answer 10

Ok no problem. Anything to the power of zero equals 1. Does this help?

Answer 11

yes.

Answer 12

So now you have 2^m = 1/16, can you finish it?

Answer 13

give me a sec please =)

Answer 14

nope. how does 1 apply here?

Answer 15

Okay there's a couple of ways to do this now, if you've been taught logarithms in school you could take log_2 (logarithm base 2) of both sides to get m = log_2(1/16)

Answer 16

i haven't worked on logs yet. should i get to it first before i solve these problems? =)

Answer 17

Or if you just think about it 2^(-1) =1/2, and 1/2 squared is 1/4, then 1/4 squared is 1/16, so by inspection you can see that 2^(-4) = 1/16

Answer 18

But yeah for more complex problems you would need logs

Answer 19

i'll get to it then. thank you!