Question

Which equation shows the quadratic function used to solve 7x^2=9+x for x?

Answer 1

Answer:

Step-by-step explanation:

Answer 2

For this case we have the following equation of the second degree:

$7x ^ 2 = 9 + x$

Rewriting:

$7x ^ 2-x-9 = 0$

The solutions will be given by the following equation:

$x = \frac {-b \pm \sqrt {b ^ 2-4 (a) (c)}} {2a}$

We have to:

$a = 7\\b = -1\\c = -9$

Substituting the values:

$x = \frac {- (- 1) \pm \sqrt {(- 1) ^ 2-4 (7) (- 9)}} {2 (7)}\\x = \frac {1 \pm \sqrt {(- 1) ^ 2 + 4 (7) (9)}} {2 (7)}$

Answer:

Option D