Question

X2 – 1x – 90 = 0 has solutions {a, b}. What is a + b?

Answer 1

a + b =1

Explanation:

Write the given quadratic as x^2 – 1x – 90 = 0. This factors into

(x - 10)(x + 9) = 0, and so the roots/solutions are {-9, 10}.

If we call -9 "a" and 10 "b," then the sum a + b is -9 + 10, or a + b =1.