Question - Expression Simplification

To simplify the expression, we first expand the terms:

1. 5x(2a) + 5x(3) - 4(6a) = 10ax + 15x - 24a.

2. Combine like terms with 10x² + 15d - 8x - 12.

Final expression: 10x² + (15d - 8x) - 24a - 12