Question

The equation x2 – 1x – 90 = 0 has solutions {a, b}. What is a + b?

–19
–9
1
10

Answer 1

-9 and 10 are the solutions, so -9+10=1

Answer 2

(when dealing with negatives it is re-agranged like so, 10-9 rather then -9+10)