Is this an example of Associative property of multiplication (7×8)x 9=7×(8×9)

Yes, this is an example of the associative property of multiplication. The associative property states that when multiplying three or more numbers together, the way the numbers are grouped does not change the product. In this case, by moving the parentheses around in the equation, the grouping of the numbers changes, but the product remains the same.