## Algebra 1

$4a$
We start with the given expression: $4ab^0$ The zero as an exponent rule states that for every nonzero number $a$, $a^0=1$. We use this to simplify to $4a\times1$. The identity property of multiplication states that the product of any real number and $1$ is the original number. We use this property to reduce the expression to $4a$.