5+5+5-5+5-5+5x0=?

5 + 5 + 5 – 5 + 5 – 5 × 0 

=5 + 5 + 5 – 5 + 5 – 0

=20 – 5

=15

However if you meant, (5 + 5 + 5 – 5 + 5 – 5 )× 0

then the answer is 0.