(0,9у + 18)(0,5-2у) = 0;

To solve the equation \((0.9y + 18)(0.5 - 2y) = 0\), we will use the zero product property. This property states that if a product of factors equals zero, at least one of the factors must equal zero. Therefore, we can set each factor to zero individually:

1. First Factor: \[ 0.9y + 18 = 0 \] To solve for \(y\), subtract 18 from both sides: \[ 0.9y = -18 \] Now, divide by 0.9: \[ y = \frac{-18}{0.9} = -20 \]

2. Second Factor: \[ 0.5 - 2y = 0 \] To solve for \(y\), add \(2y\) to both sides: \[ 0.5 = 2y \] Now, divide by 2: \[ y = \frac{0.5}{2} = 0.25 \]

The solutions to the equation \((0.9y + 18)(0.5 - 2y) = 0\) are: \[ y = -20 \quad \text{or} \quad y = 0.25 \]