Question

Blahhh, I hate logs. Someone refresh my memory. Here is the graph of y = f(x):

Answer 1

Last time I did this was two years ago. Please refresh my memory.

Answer 2

I think there can be more than one answer.

Answer 3

Don't you have to simplify it algebraically first...?

Answer 4

Logarithm is not defined for negative values.
Go through each choice and rule out the choices where log( negative number ) occurs.

Answer 5

@ Idkwut, I don't particularly remember how to simplify algebraically for logs. @ ranga, so we can rule out the last log log6 (-(ax^3)) where a > 0 ?

Answer 6

No, the graph show the log curve for negative x.
So assume x is negative in all three choices.
In each choice they tell you if a is positive or negative.
Use those two info to see if we end up taking log of a negative number. If so, rule out that choice.

Answer 7

no, that one is actually the right choice

Answer 8

Then I can rule out the second choice, yes?

Answer 9

yes

Answer 10

You can rule out the first one, because you have an even power of an negative number, which is going to be positive, but has a negative coefficient, so the argument to the log is negative.

You can rule out the second one, because you have an odd power of a negative number, and a positive coefficient, so the result will be negative and the argument to the log is negative.

The third one has an odd power of a negative number, which is negative, but it has a negative coefficient, so it becomes positive.

Answer 11

Ah, I see. I realized just right before you posted. Thank you!

Answer 12

Thank you too randa!

Answer 13

Alright.