Problem
springfieldpublicschools.instructure.com Question 8 $1 \mathrm{pts}$ Which of the given quadratic equations has root $x=-i \sqrt{5}$ ? Select all that apply. $y=x^{2}+5$ $y=x^{2}-5$ $y=-x^{2}-5$ $y=x^{2}-25$ $y=-5 x^{2}-25$ $y=(x+5)^{2}$ $y=-x^{2}-25$
Solution
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 ：\(\boxed{y=x^{2}+5, y=-x^{2}-5, y=-5 x^{2}-25}\)
