Question

Sabendo ( pergunta na foto )

Answer 1

Resposta:

○ -4 e 5

Explicação passo-a-passo:

$\sqrt{x {}^{2} - 9} = \sqrt{x + 11}$

$( \sqrt{x {}^{2} - 9} ) {}^{2} = ( \sqrt{x + 11} ) {}^{2}$

$x {}^{2} - 9 = x + 11 \\ x {}^{2} - x - 9 - 11 = 0 \\ x {}^{2} - x - 20 = 0$

a=1. b=-1 e c=-20

$delta = b {}^{2} - 4ac$

$delt = ( - 1) {}^{2} - 4 \times 1 \times - 20 = 1 + 80 = 81$

$\sqrt{81} = 9$

x'=[-(-1)+9]/2.1

x'=[1+9]/2

x'=10/2

x'=5

x"=[-(-1)-9]/2.1

x"=[1-9]/2

x"=-8/2

x"=-4