Answer:
I'm not sure from my answer but I'm going to try
A = { a^2 - 4 = 0 }
A = { a^2 = 0+ 4 }
A = { a^2 = 4}
Take root of both sides
A = {a = 2}
A = {2}
B = { -2, -1, 0, 1, 2}
C = { 1, 2, 3, 4, 5, 6,7}
i) A\B
= {2} \ {-2,-1,0,1,2}
= ⌀ ( "null set" )
ii) (A\B) \C
= ( {2} \ {-2,-1,0,1,2} ) \ C
= ⌀ \ C
= ⌀ \ { 1, 2, 3, 4, 5, 6,7}
= ⌀ ( "null set" )
iii) (A ∪ B) \ C
= ( { 2 } ∪ { -2, -1, 0, 1, 2} ) \ C
= { -2, -1, 0, 1, 2} \C
= { -2, -1, 0, 1, 2} \ { 1, 2, 3, 4, 5, 6,7}
= { -2, -1, 0 }
iv) ( A\B) ∩ ( A\C)
= ( { 2 } \ {-2,-1,0,1,2} ) ∩ ( { 2 } \ { { 1, 2, 3, 4, 5, 6,7} )
= ⌀ ∩ ⌀
= ⌀
v) ( A ∩ B ) \ C
= ( { 2 } ∩ { -2, -1, 0, 1, 2 } ) \ C
= { 2 } \ { 1, 2, 3, 4, 5, 6, 7 }
= ⌀ "null set"
and 
, if 
is an arithmetic sequence, then the common difference between successive terms is 
.
th term is