I cannot reach a meaningful solution from the given information. To prove that S was always true, you would have to prove that N was always false. To prove that N was always false you would have to prove that L was always false. For the statement (L ^ T) -> K to be true, you only need K to be true, so L can be either true or false.
Therefore, because of the aforementioned knowledge, I do not believe that you can prove S to be true.
Answer:I pretty sure it will be 12.5
I subtracted the total cost for the guitar by the money he already had and got 250
Then I did 250/20 and got 12.5
250 is the money that he still needs for the guitar
Hope it helps

will be increasing on the intervals where

and decreasing wherever

. Local extrema occur when

and the sign of

changes to either side of that point.

is positive when

is between -4 and some number between -2 and -1, and also 2 (exclusive) and 4, so you can estimate that

is increasing on the intervals [-4, -2] and (2, 4].

is negative when

is between some number between -2 and -1, up to some number less than 2. So

is decreasing on the interval [-1, 1].
You then have two possible cases for extrema occurring. The sign of

changes for some

between -2 and -1, and again to either side of

.
2
3
-7
24
-25
-3
second row
-12
-2
-9
-38
10
-28