Sets and Relations Part 1

A = {x ∊ z : 2(x+2)(x2−5x+6) = 1}
2(x+2)(x2−5x+6) = 20 ⇒ x = - 2 , 2 , 3
A = {- 2 , 2 , 3}
B = { x ∊ Z ; - 3 < 2x - 1 < 9}
B = {0 , 1 , 2 , 3 , 4}
A × B has is 15 elements so number of subsetsof A × B is 215.