Question

A = {1, 3, 5, 7, 9}
B = {2, 4, 6, 8, 10}
C = {1, 5, 6, 7, 9}
A(B∩C) =?

Answer 1

what is symbol after A ?

Answer 2

A(B∩C) ={1, 3, 5, 6, 7, 9}

Answer 3

\[B\cap C= \left\{ 6 \right\}\]
is there really no sign inbetween A and (BnC)?

Answer 4

I assume you mean A*(B∩C)...The value at which B intersects C is 6 (as joemath pointed out).

Multiplying the entire set A by 6 gives {6, 18, 30, 42, 54}.