Digital Electronics - Logic Gates

In the circuit shown below, X and Y are digital inputs, and Z is a digital output. The equivalent circuit is a

For a 3-input logic circuit shown below, the output Z can be expressed as

In the logic circuit shown in the figure, Y is given by

The logical gate implemented using the circuit shown below where, V₁ and V₂ are inputs (with 0 V as digital 0 and 5 V as digital 1) and VOUT is the output, is