Answer
$(3\times10)\times z$
Work Step by Step
The associative property of multiplication holds that $(a\times b)\times c=a \times (b\times c)$.
In this example, we can set $a \times (b\times c)=3\times(10\times z)$.
Therefore, $a=3$, $b=10$, and $c=z$, so an equivalent expression would be $(a\times b)\times c=(3\times10)\times z$.