It could be 28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43, or 44.

The number "x" is given by:
Therefore, we have:
Since the sweater is now 30% off, that means it is selling for 70% of it's original price ( 100% - 30% = 70%).
Multiply the original price by 70%:
52 x 0.70 = 36.40
The sale price is $36.40
ANSWER
Katnis is right
EXPLANATION
We use the Remainder Theorem to check if she is right.
According to the Remainder Theorem, if the polynomial function,

is divided by x+1, then the remainder is given by

We substitute x=-1 into the function to obtain,

We simplify to get:



Katnis is right because the remainder is zero