To factor the expression \( 30x + 70 \), we first look for the greatest common factor (GCF) of the terms.
The GCF of \( 30 \) and \( 70 \) is \( 10 \).
Now we can factor out \( 10 \):
\[ 30x + 70 = 10(3x + 7) \]
So, the equivalent factorization is:
10(3x + 7)
Thus, the correct response is:
10(3x+7).