Given that the variables x and y have already been declared and assigned values, write an expression that evaluates to true if x is non-negative and y is negative. so, if the value of x were 4 and the value of y were -3 then the expression would be true. on the other hand, if the value of x were 4 and the value of y were 1 then the value of the expression would be false. 2-write the definition of a class clock . the class has no constructors and two instance variables. one is of type int called hours and the other is of type boolean called isticking