For this case we have the following equation of the second degree:
[tex]7x ^ 2 = 9 + x[/tex]
Rewriting:
[tex]7x ^ 2-x-9 = 0[/tex]
The solutions will be given by the following equation:
[tex]x = \frac {-b \pm \sqrt {b ^ 2-4 (a) (c)}} {2a}[/tex]
We have to:
[tex]a = 7\\b = -1\\c = -9[/tex]
Substituting the values:
[tex]x = \frac {- (- 1) \pm \sqrt {(- 1) ^ 2-4 (7) (- 9)}} {2 (7)}\\x = \frac {1 \pm \sqrt {(- 1) ^ 2 + 4 (7) (9)}} {2 (7)}[/tex]
Answer:
Option D
