Question

Ajudem a resolver, por favor. X² = 3√2² . 7² - 2.3√2 .√2/2
                                 

Answer 1

$x^2=3 \sqrt{2^2}.7^2-2.3 \sqrt{2} . \sqrt{\frac{2}{2}} \\x^2=3.2.7^2-6 \sqrt{2} .1\\x^2=6.49-6 \sqrt{2} \\x=\pm \sqrt{6(49- \sqrt{2}) }$