Question

Can someone explain this pls

Answer 1

Answer:

Step-by-step 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:

$x_{12}$ = $\frac{- 14 }{2}$ ± $\frac{6\sqrt{2}i }{2}$

$x_{12}$  = - 7 ± 3√2 i