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Question 8
$1 pts$
Which of the given quadratic equations has root $x = - i \sqrt{5}$ ? Select all that apply.
$y = x^{2} + 5$
$y = x^{2} - 5$
$y = - x^{2} - 5$
$y = x^{2} - 25$
$y = - 5 x^{2} - 25$
$y = (x + 5)^{2}$
$y = - x^{2} - 25$

Answer

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Answer

$y = x^{2} + 5, y = - x^{2} - 5, y = - 5 x^{2} - 25$

Steps

Step 1 ：Plug the value $x = - i \sqrt{5}$ into each equation and see if it satisfies the equation.

Step 2 ： $y = (- i \sqrt{5})^{2} + 5$ is satisfied

Step 3 ： $y = - (- i \sqrt{5})^{2} - 5$ is satisfied

Step 4 ： $y = - 5 (- i \sqrt{5})^{2} - 25$ is satisfied

Step 5 ： $y = x^{2} + 5, y = - x^{2} - 5, y = - 5 x^{2} - 25$