(2) {x|x=3}

(3) x 2-5x+4 = 0 is (x-4)(x- 1)=0, so {x | x = 1 or x=4}

{ x | x & gt 1/3}

(5) X 2+2 = 0, the shift term X 2 =-2, and the solution is an empty set because X 2 is greater than or equal to 0.

(6){-4,-3,-2,- 1,0, 1,2,}

(7) {x|x= 1 or x=0}

(8){ x∈Z | x = 2n； N is an integer}

(9){ x∈Z | x = 2n- 1； N is an integer}

Because a subset of a set can contain itself, proper subset does not contain itself;

{x|x≥5} and {x | 5}

All subsets of {a, b, c}: empty set, {a}, {b}, {c} {a, b} {a, c} {b, c} {a, b, a}

Proper subset: empty set, {a}, {b}, {c} {a, b} {a, c} {b, c}