8x*3y*(-5y) -7x²*(-4y)

Let's simplify the expression step by step:

The original expression is:

\[ 8x \cdot 3y \cdot (-5y) - 7x^2 \cdot (-4y) \]

1. First, simplify \( 8x \cdot 3y \cdot (-5y) \): \[ 8 \cdot 3 \cdot (-5) \cdot x \cdot y \cdot y = -120xy^2 \]

2. Next, simplify \( -7x^2 \cdot (-4y) \): \[ -7 \cdot (-4) \cdot x^2 \cdot y = 28x^2y \]

3. Now, combine the two results together: \[ -120xy^2 + 28x^2y \]

The simplified expression is:

\[ 28x^2y - 120xy^2 \]

This is the final simplified expression.