Question

equações de 2 grau 5(x²-1)=4(x²+1) me ajudem !!?​

Answer 1

$5(x^2-1)=4(x^2+1)\\5x^2 - 5 = 4x^2 + 4\\5x^2 - 4x^2 = 4 + 5\\x^2 = 9\\x = \pm\sqrt9\\\\x_1 = -3\\ x_2 = 3\\\\\\\boxed{\boxed{S = \{-3; \ 3\}}}$