Question

Which logarithmic graph can be used to approximate the value of y in the equation 2y = 5?

Answer 1

did you type that correctly? There is not need for logs in that eq

Answer 2

http://gyazo.com/94ece37b12e563e25a60b4aa5e649dc1

Answer 3

yes i did
heres the graphs

Answer 4

http://gyazo.com/87e0bee511b6f506f266bb9500bb2157

Answer 5

well, solve your eq for y to begin

Answer 6

how do i do that?

Answer 7

you don't know how to solve 2y=5 for y?

Answer 8

its 2^y=5

Answer 9

that makes more sense now

Answer 10

alright, so, in order to get y out of the exponent, we need to undo it. The opposite of the exponent function is the log function. now, there are different bases for logs, you can have log base anything. Here we can use log base 2 to undo, 2^y

Answer 11

just remember we need to do this to both sides

Answer 12

so 2*^2 ?

Answer 13

not, quite. We write it like this \[log_2(2^y)=log_2(5)\]

Answer 14

so now, we know that the log base 2 undo's the 2^y, so we are just left with y. and we get \[y=log_2(5)\] so now, you just plug it into your calculator and see which point marked is closer.

Answer 15

but again, I think there is a type-o because none of those are a horizontal line.

Answer 16

thats excatly how i copied it from the problem

Answer 17

could it be the last graph? @FibonacciChick666

Answer 18

well, what is log base 2 of 5? (you can use wolfram alpha to figure that out if you wish)

Answer 19

just a couple of decimal places, not all of em

Answer 20

it was the last graph

Answer 21

I know that is the only option(even though this is a very poorly phrased question), I just wanted to make sure you could figure out that value.