Is the set `{x in R : x^2 = -2}`, an empty set?

What is the set : {x:x in R, x^2=9, 2x=4} ?

Show that each of the relation R in the set A = {x in z : 0 le x le 12} , given by R = {(a,b) : |a-b| is a multiple of 4} is an equivalec relation. Find the set of all elements related to 1 in each case.

Show that each of the relation R in the set A = {x in Z : 0 le x le 12} , given by: R = {(a, b) : a = b} , is an equivalence relation. Find the set of all elements related to 1 in each case.

The set A= {x: x^2 =4, x is odd} is :

Whether the following is empty (null) set? { x :x^2 =25 and x is an even integer}.

The set of A= {x:x in R, x^2=16 and 2x=6} equals :

Show that the relation R in the set R given by : R ={(x, y): x le y^2) is neither reflexive nor symmetric nor transitive.

State whether the following statement is true or false. If the statement is false, rewrite the given statement correctly. If A and B are non-empty sets, then A xx B is a non-empty set of ordered pairs (x, y) such that x in A and y in B .