Question

me ajudem por favor!!​

Answer 1

Resposta:

a) $x=\frac{20}{7}$

$3x^{2} +4x^{2}= 20^{2} \\\sqrt[]{7x^{2} } =\sqrt[]{20^{2} } \\7x=20\\x= \frac{20}{7}$

b) $x^{2} +6^{2} =(3\sqrt{5}^{2} ) \\x^{2} +36= 3*3*5\\x^{2} = 45-36\\x^{2} = 9\\\sqrt{x}^{2} = \sqrt{9} \\x=3$