To solve the equation \( 6.24(x + 5.9) = 20.22 \), we start by reversing the multiplication on the left side. To do this, we divide both sides of the equation by \( 6.24 \).
So, the number that both sides should be divided by is \( 6.24 \).
Now you can divide both sides of the equation:
\[ \frac{6.24(x + 5.9)}{6.24} = \frac{20.22}{6.24} \]
This simplifies to:
\[ x + 5.9 = \frac{20.22}{6.24} \]
After that, you can proceed to solve for \( x \).