Here is a quadratic equation along with its solution. There's only 1 thing I don't understand. In the brackets how do we know that the values are - 4 and - 5 as opposed to + 4 and + 5. Why are they both negative when the quadratic contains both a negative and a positive expression?(adsbygoogle = window.adsbygoogle || []).push({});

x^{2}- 9 + 20 = 0

(x - 4) (x - 5) = 0

x = 4 or 5

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# Homework Help: Quadratic equation

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