Construct truth table for the function `X` of `A` and `B` as shown in the figure.

Explanation

Fist write the Boolean expression on the figure and then construct truth table
(a)
`|(A,B,A+B,X=A.(A+B)),(0,0,0,0),(0,1,1,0),(1,0,1,1),(1,1,1,1)|`
(b)
`|(A,B,bar(A),bar(B),bar(A)+B,A+bar(B),X=bar((bar(A)+B)+(A+bar(B)))),(0,0,1,1,1,1,0),(0,1,1,0,1,0,0),(1,0,0,1,0,1,0),(1,1,0,0,1,1,0)|`