Question

Which are the solutions of x2 = -7x-8?

03:49
03 -3-17
07-37 +17
0 -7-7 -7 + 417

Answer 1

For this case we have the following quadratic equation:

`x ^ 2 + 7x + 8 = 0`

Where:

`a = 1\\b = 7\\c = 8`

We solve by the following formula:

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

Substituting we have:

`x = \frac {-7 \pm \sqrt {7 ^ 2-4 (1) (8)}} {2 (1)}\\x = \frac {-7 \pm \sqrt {49-32}} {2}\\x = \frac {-7 \pm \sqrt {49-32}} {2}\\x = \frac {-7 \pm \sqrt {17}} {2}`

Thus, we have two roots:

`x_ {1} = \frac {-7+ \sqrt {17}} {2}\\x_ {2} = \frac {-7- \sqrt {17}} {2}`

Answer:

`x_ {1} = \frac {-7+ \sqrt {17}} {2}\\x_ {2} = \frac {-7- \sqrt {17}} {2}`