
Patrick B. answered 02/09/21
Math and computer tutor/teacher
Vx mean FOR ALL X in the set
---------------------------------------
a) If The number is divisible by 16 then the number is divisible by 8
(x mod 16 = 0) --> (x mod 8)=0
b) If XY=0 then x=0 or y=0 for any real numbers x and y
Vx in R, (xy=0) --> (x=0) v (y=0)
c) is X is rational then X^2 is rational
(Vx in Q) X^2 in Q