I think "price" = value

a) A(x) = 0 if any of the 3 factors is zero.

So,

x-1 = 0 <----x = 1

2-x = 0 <----x = 2

6 +2x = 0

2x = 0 -6

x = -6/2 = -3

Therefore, A(x) = 0 if x=1, or x=2, or x = -3. -------------answer.

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b)

To give A(x) not equal to zero is to not let x equal to 1 or 2 or -3.

Or x is not equal to 1, not equal to 2, or not equal to -3. And x can be any number except those 3 numbers. ------------answer.

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c)

So that A(x) has an inverse or reverse?

Sorry, I don't understand that.