Question

9x²=25+8x² me ajuda tbm pessoal?/?

Answer 1

$9 x^{2} =25+8 x^{2} \to \\\\\\ 9 x^{2} -8 x^{2} =25 \to \\\\ x^{2} =25\to\\\\ x= +- \sqrt{25} \to \\\\x=+-5\\\\\\ S=(-5,5)$