Please answer question 6 and 7

6)Using basic identities of Boolean algebra, prove or disprove the following equations: a) (X + Y). (X + Y') = X b) (x) (X + Y) = X c) (X) . (X + Y') = X d) (X + Y). (X' + Z) = X Z +X' Y e) XYZ + X Y = XY+XZ 7)Simplify the following expressions as much as possible: a) (x + y)(x' + y)(x + y')(x' + y) b) x': (y' + z')(x + y + z') c) A.B. (D' + C D) + B(A + A' CD ) d) xy + y2 + x' .Z 2