Question

Can someone explain this pls

Answer 1

Explanation:

( g ° f )(x) = ( x + 7 )² = x² + 14x + 49

20 + 3(x² + 14x + 49) = - 34

20 + 3x² + 42x + 147 = - 34

3x² + 42x + 201 = 0 ⇔ x² + 14x + 67 = 0

D = 196 - 268 = - 72 < 0

There is no any roots in set of real numbers.

The values of x in set of complex numbers are:

`x_(12)` =
`(- 14 )/(2)` ±
`(6√(2)i )/(2)`

`x_(12)` = - 7 ± 3√2 i