For which of the following, y can be a function of `x, (x in R, y in R)?`

For which y can be a function of x. (x in R, y in R) x^4=y^2

For which y can be a function of x. (x in R, y in R) x^6=y^3

For which y can be a function of x. (x in R, y in R) y^2=4ax

For which y can be a function of x. (x in R, y in R) 3y=(logx)^2

For which y can be a function of x. (x in R, y in R) (x-h)^2+(y-k)^2=r^2

Which one of the following is not a function? {(x , y): x , y in R , x^2=y} b. {(x , y): x , y in R , y^2=x} c. {(x , y): x , y in R , x=y^3} d. {(x , y): x , y in R , y=x^3}

Which of the following are function: {(x , y): y^2=x , x , y in R} b. {(x , y): y=|x|, x , y in R} c. {(x , y): x^2+y^2=1, x , y in R} d. {(x , y): x^2-y^2=1, x , y in R}

If x,y in R then which one is never be a function?

In the set Z of all integers, which of the following relation R is not an equivalence relation? x\ R\ y : if xlt=y (b) x\ R\ y : if x=y (c) x\ R\ y : if x-y is an even integer (d) x\ R\ y : if x=y (mod 3)