Respuesta :

Answer:

D

Step-by-step explanation:

Given a quadratic equation in standard form : ax² + bx + c = 0

We can solve for x using the quadratic formula

x² + 2x + 9 = 0 ← is in standard form

with a = 1, b = 2 and c = 9

x = ( - 2 ± [tex]\sqrt{2^2-(4(1)(9)}[/tex]) / 2

  = ( - 2 ± [tex]\sqrt{4-36}[/tex]) / 2

  = (- 2± [tex]\sqrt{-32}[/tex]) / 2)

  = (- 2 ± [tex]\sqrt{16(2)(-1)}[/tex]) / 2

  = ( - 2 ± 4i[tex]\sqrt{2}[/tex]) / 2

  = [tex]\frac{-2}{2}[/tex] ± [tex]\frac{4i\sqrt{2} }{2}[/tex]

  = - 1 ± 2i[tex]\sqrt{2}[/tex] → D

zainebamir540

Answer:

Choice D is the answer.

Step-by-step explanation:

We have given a quadratic equation.

x²+2x+9 = 0

We have to find the solution of given equation.

From given equation, a = 1, b = 2 and c = 9.

x = (-b±√b²-4ac) / 2a is quadratic formula to find the solve quadratic equation.

Putting given values in formula, we have

x = (-2±√(2)²-4(1)(9) ) / 2(1)

x = (-2±√4-36) / 2

x = (-2±√-32) / 2

x = (-2±√16√-2 ) /2

x = (-2±4√2√-1) / 2                                 ∵ i = √-1

x = 2(-1±2√2i) / 2

x = -1±2√2i is the solution of given solution.

Otras preguntas