15a^3b+30a

To simplify the expression \( 15a^3b + 30a \), we can factor out the greatest common factor (GCF) from both terms.

1. Identify the GCF:

   • The coefficients are 15 and 30; the GCF of 15 and 30 is 15.
   • For the variable part, \( a^3 \) is the highest power of \( a \) that appears in the first term, while \( a \) appears in the second term. The GCF here is \( a \).

2. Factor out the GCF: \[ 15a^3b + 30a = 15a(a^2b + 2) \]

So, the expression \( 15a^3b + 30a \) simplifies to: \[ 15a(a^2b + 2) \]