Question

$4x {}^{2} + 20 = 0{}^{}$
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Answer 1

$4 {x}^{2} + 20 = 0 \\ \\ = > 4( {x}^{2} + 5) = 0 \\ \\ = > {x}^{2} + 5 = \frac{0}{4} = 0 \\ \\ = > {x}^{2} = - 5 \\ \\ = > x = \sqrt{5} \\ or \\ x = - \sqrt{5}$