-5(3m³ + 7n²) + 8n²
First, let's use the distributive property to eliminate the parentheses and distribute -5 inside them.
-15m³ + -35n² + 8n²
Now, let's combine the like terms.
-15m³ - 27n²
Now, we have to find the GCF (greatest common factor) for the expression, and divide all of the terms by it.
-3 (5m³ + 9n²)
your final answer simplified expression is -3 (5m³ + 9n²)