Let * be defined as x * y = x' + y. Let z = x * y. Value of z * x is

1997

Let * be defined as

x * y = x' + y. 

Let

z = x * y. 

Value of

z * x

is

  1. A.

    x'+y

  2. B.

    x

  3. C.

    0

  4. D.

    1

Attempted by 41 students.

Show answer & explanation

Correct answer: B

The problem defines a custom operation (*) as: x * y = x' + y (which is equivalent to the logical implication x -> y)

We are given: z = x * y = x' + y

Now, we need to find the value of: z * x

Using the definition of the operation (*), we substitute z as the first operand and x as the second operand: z * x = z' + x

Now, substitute the value of z (which is x' + y) into this expression: z * x = (x' + y)' + x

Apply De Morgan's Law to simplify the term (x' + y)': (x' + y)' = (x'') * y' = x * y'

Substitute this back into the equation: z * x = (x * y') + x

Apply the Distributive Law of Boolean algebra [A + (B * C) = (A + B) * (A + C)]: (x * y') + x = x + (x * y') = (x + x) * (x + y') = x * (x + y') = x

Alternatively, you can use the Absorption Law [A + (A * B) = A]: x + (x * y') = x

Therefore, the final simplified value of z * x is x.

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