Answer:

Step-by-step explanation:

N4=c
n times 4, n being a number of notebooks, would equal c, or the overall cost.
The illegal values of b are when the denominator equals 0.
So,
gives you (b-4)(b+2)=0
Therefore, b=4 and b=-2, which is answer A.
The answer would be D Because one side is 18 and another is 26 and 18 times 26 is 468.