Answer:
C
Step-by-step explanation:
Use the quadratic formula
[tex]x = \frac{ - b + - \sqrt{{b}^{2} - 4ac}}{2a} [/tex]
(the plus and minus sign just means that there must be an answer plus the square root and subtracted)
Let a=1, b=9 and c=-11 and plug in the variables.
[tex]x = \frac{ - 9 + - \sqrt{ {9}^{2} - 4 \times 1 \times - 11} }{2 \times 1} [/tex]
Simplify
[tex]x = \frac{ - 9 + - \sqrt{81 + 44} }{2} [/tex]
[tex]x = \frac{ - 9 + - \sqrt{125} }{2} [/tex]
Simplify the radical
[tex]x = \frac{ - 9 + - \sqrt{25} \sqrt{5} }{2} [/tex]
[tex]x = \frac{ - 9 + - 5\sqrt{5} }{2} [/tex]
Then, adding and subtracting the square root, you get:
[tex]x = \frac{ - 9 + 5\sqrt{5} }{2}[/tex]
And
[tex]x = \frac{ - 9 - 5\sqrt{5} }{2}[/tex]
Hope this helps :)
