The equation x2 - 1x - 90 = 0 has solutions {a, b}. What is a + b?
-19, -9, 1, 10
 

Solution:

Given The equation x² - 1x - 90 = 0 has solutions

we have the quadratic formula /{-b±√(b² -4ac)} / 2a to find roots.

a = 1; b = -1 , c = -90

⇒ {-(-1) ± √((-1)² -4(1)(-90)} / 2

⇒{1 ± √361} / 2

= {1 ± 19} / 2a = 10, -9

a = 10, b = -9

⇒ a + b = 10-9

⇒ a + b = 1

The equation x² - 1x - 90 = 0 has solutions {a, b}. What is a + b?
-19, -9, 1, 10

Summary:

The equation x² - 1x - 90 = 0 has solutions {a, b}. The value of a + b is 1.