Answer:
x(1,2) = -5 ± √61) / (-2)
Step-by-step explanation:
The ABC formula of quadratic equation states
x(1,2) = (-b ± √b^2 - 4ac) / 2a
-x^2 + 5x + 9 = 0
a = -1
b = 5
c = 9
Thus x(1,2) = (-b ± √b^2 - 4ac) / 2a
= (-5 ± √(-5)^2 - 4*(-1)*9) / 2*(-1)
= (-5 ± √25+36) / (-2)
= (-5 ± √61) / (-2)
