Question

0 conjunto verdade em R da equação x.(x + 1) = 30 é:

a) {6,5} b) {5, - 6} c) {-5, 6}. d) {2,-5}​

Answer 1

Resposta:

OLÁ

VAMOS A SUA PERGUNTA:⇒⇒

$\sf x^2+x-30=0$

$\sf x=\dfrac{-1\pm\sqrt{1^2-4(-30)} }{2}$

$\sf x=\dfrac{-1\pm\sqrt{1-4(-30)} }{2}$

$\sf x=\dfrac{-1\pm\sqrt{1+(120)} }{2}$

$\sf x=\dfrac{-1\pm\sqrt{121} }{2}$

$\sf x=\dfrac{-1\pm11}{2}$

$\sf x=\dfrac{10}{2}$

$\sf \green{x=5}$

$\sf x=\dfrac{-12}{2}$

$\sf \blue{x=-6}$

$\boxed{\bold{\displaystyle{\clubsuit\ \spadesuit\ \maltese\ \sf \sf \green{x=5} }}}\ \checkmark\\\boxed{\bold{\displaystyle{\clubsuit\ \spadesuit\ \maltese\ \sf \sf \blue{x=-6} }}}\ \checkmark$←←↑↑ RESPOSTA.

Explicação passo-a-passo:

ESPERO TER AJUDADO

Answer 2

Oie, Td Bom?!

■ Resposta: Opção B.

$x \: . \: (x + 1) = 30$

$x {}^{2} + x = 30$

$x {}^{2} + x - 30 = 0$

• Coeficientes:

$a = 1 \: , \: b = 1 \: ,\: c = - 30$

• Fórmula resolutiva:

$x = \frac{ - b± \sqrt{b {}^{2} - 4ac } }{2a}$

$x = \frac{ - 1± \sqrt{1 {}^{2} - 4 \: . \: 1 \: . \: ( - 30)} }{2 \: . \: 1}$

$x = \frac{ - 1± \sqrt{1 + 120} }{2}$

$x = \frac{ - 1± \sqrt{121} }{2}$

$x = \frac{ - 1±11}{2}$

$⇒ x= \frac{ - 1 + 11}{2} = \frac{10}{2} = 5$

$⇒x = \frac{ - 1 - 11}{2} = \frac{ - 12}{2} = - 6$

$S = \left \{ - 6 \: ,\: 5 \right \}$

Att. Makaveli1996