Question

4×ao quadrado menos 20 = 0

Answer 1

$4{x}^{2} \: - \: 20 \: = \: 0$

$4{x}^{2} \: = \: 20$

${x}^{2} \: = \: \frac{20}{4}$

${x}^{2} \: = \: 5$

$x \: = \:±\sqrt{5}$

$x \: = \: \sqrt{5} ; \: - \sqrt{5}$