To solve the equation \(\frac{5}{8}(x - \frac{1}{2}) = 10\), the first step is to eliminate the multiplication by \(\frac{5}{8}\).
To do this, you can divide both sides of the equation by \(\frac{5}{8}\).
Dividing by a fraction is equivalent to multiplying by its reciprocal, so instead of dividing, you can multiply both sides by \(\frac{8}{5}\).
Therefore, the number both sides should be multiplied by (or the equivalent operation to reverse the multiplication) is \(\frac{8}{5}\) (or you could also think of it as dividing both sides by \(\frac{5}{8}\)).