Answer is 49
Formula is b^2-4(ac)
3^2-4(2*-5) while a=2, b=3, c=-5
9-4(2*-5)
9-4(-10)
9+40
49
Hope this helps!
We can see the sequence goes by decreasing 9 on each number
so the numbers are
2, -7, -16, -25, -34, -43, -52, -61, -70
so adding all these numbers we get
2-7-16-25-34-43-52-61-70
= -306
hope this helped