Answer
$(5\times7)\times x$
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 $a \times (b\times c)=5\times(7\times x)$.
Therefore, $a=5$, $b=7$, and $c=x$, so an equivalent expression would be $(a\times b)\times c=(5\times7)\times x$.