81x^2=64

解

81 x^{2} = 64

x = \frac{8}{9}, x = - \frac{8}{9}

十進法表記

x = 0.88888 \dots, x = - 0.88888 \dots

解答ステップ

81 x^{2} = 64

以下で両辺を割る

81

x^{2} = \frac{64}{81}

x^{2} = f (a)

の場合, 解は

x = f (a), - f (a)

x = \frac{64}{81}, x = - \frac{64}{81}

\frac{64}{81} = \frac{8}{9}

- \frac{64}{81} = - \frac{8}{9}

x = \frac{8}{9}, x = - \frac{8}{9}