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When two or more numbers are multiplied together, it gives a number. The numbers that are multiplied are called the factors. And the result of the multiplication of numbers is called the product of those numbers.

Suppose a, b, and c is three real numbers.

Associative property of Multiplication

Property:$\text{(a}  ·  \text{b)}  ·  \text{c}=\text{a}  ·  ( \text{b}  ·  \text{c} )$

If you are multiplying three real numbers, the product is always the same regardless of their grouping.

Example:$\text{(6}  ·  \text{4)}  ·  \text{3}=\text{6}  ·  ( \text{4}  ·  \text{3} )  =  72$

To evaluate the expression$5x^{2}y$, substitute the value of x as negative and y as 20 and multiply the numbers as shown below,

$5x^{2}y  \text{when}  x=-  6  \text{and}  y=20$

localid="1650110373765" $\begin{array}{l}\text{ â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰}5\text{ }·\text{ â¶Ä‰}{x}^2\text{ }·\text{ }y\text{ }\\ =\text{ â¶Ä‰}5\text{ }·{\left(-6\right)}^2\text{ â¶Ä‰}·\text{ }\left(20\right)\text{ â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â€‰Substitute â¶Ä‰the â¶Ä‰value â¶Ä‰}x=−\text{ â¶Ä‰}6\text{ â¶Ä‰and â¶Ä‰}y=20\\ =\text{ â¶Ä‰}5\text{ â¶Ä‰}·\text{ â¶Ä‰}(36\text{ â¶Ä‰}·\text{ â¶Ä‰}20\text{ })\text{ â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â€‰â¶Ä‰}(\text{Associative â¶Ä‰Property â¶Ä‰of â¶Ä‰Multiplication)}\\ =(5\text{ â¶Ä‰}·\text{ â¶Ä‰}36)\text{ â¶Ä‰}·\text{ â¶Ä‰}20\text{ â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â€‰â¶Ä‰â€‰}(\text{Associative â¶Ä‰Property â¶Ä‰of â¶Ä‰Multiplication)}\\ =\text{ â¶Ä‰}180\text{ â¶Ä‰}·\text{ â¶Ä‰}20=3600\end{array}$

Thus, the value of the expression is$5\text{ }·\text{ â¶Ä‰}{x}^2\text{ }·\text{ }y\text{ }=3600$.