x2=0,64

Given that \( x^2 = 0,64 \), you can find the value of \( x \) by taking the square root of both sides:

\[ x = \pm \sqrt{0,64} \]

Since 0.64 is a decimal, it’s often easier to work with if you convert it to a fraction:

\[ 0,64 = \frac{64}{100} = \frac{16}{25} \]

Now, take the square root:

\[ x = \pm \sqrt{\frac{16}{25}} = \pm \frac{\sqrt{16}}{\sqrt{25}} = \pm \frac{4}{5} \]

Answer:

\[ x = \pm \frac{4}{5} \]