Express the radical $$\pm \sqrt{-66}$$ using the imaginary unit, i.

<div id="id_cont_display" class="markdown-body editormd-html-preview"><textarea>Express the radical $$\pm \sqrt{-66}$$ using the imaginary unit, i.</textarea>Express the radical <math><semantics><mrow><mo>±</mo><msqrt><mrow><mo>−</mo><mn>6</mn><mn>6</mn></mrow></msqrt></mrow><annotation encoding="application/x-tex">\pm \sqrt{-66}</annotation></semantics></math>±√​−66​​​ using the imaginary unit, i.
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