Resposta :
[tex][2\sqrt[n]{4^{2x^{2}+3}} = 256\\ \sqrt[n]{4^{2x^{2}+3}} = 128\\ \sqrt[n]{4^{2x^{2}+3}} = 2^{7}\\ 4^{2x^{2}+3}} = 2^{7^{n}}\\ 4^{2x^{2}+3}} = 2^{7n}\\ 2^{2(2x^{2}+3)}} = 2^{7n}\\ 2^{4x^{2}+6}} = 2^{7n}\\ 7n=4x^{2}+6\\ 4x^{2}=7n-6\\ x^{2}=\frac{7n-6}{4}\\ x=\sqrt{\frac{7n-6}{4}}[/tex]