To simplify the expression \( 5y(8y - 3) \), you can use the distributive property, which states that \( a(b + c) = ab + ac \).
Applying the distributive property to \( 5y(8y - 3) \):
\[ 5y(8y) - 5y(3) \]
Calculating each term:
- \( 5y \cdot 8y = 40y^2 \)
- \( 5y \cdot 3 = 15y \)
Putting it all together, we get:
\[ 5y(8y - 3) = 40y^2 - 15y \]
Therefore, the expression equivalent to \( 5y(8y - 3) \) is \( 40y^2 - 15y \).