Evaluate $5 x^2 y$ whenlocalid="1650110281769" $x = -6 \text{and} y = 20$.

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" $\begin{array}{l}5·x^2·y\\ =5·{\left(-6\right)}^2·\left(20\right)\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}Substitute\hspace{0.17em}\hspace{0.17em}the\hspace{0.17em}\hspace{0.17em}value\hspace{0.17em}\hspace{0.17em}}x=-6\text{\hspace{0.17em}\hspace{0.17em}and\hspace{0.17em}\hspace{0.17em}}y=20\\ =5·(36·20)(\text{Associative\hspace{0.17em}\hspace{0.17em}Property\hspace{0.17em}\hspace{0.17em}of\hspace{0.17em}\hspace{0.17em}Multiplication)}\\ =(5·36)·20(\text{Associative\hspace{0.17em}\hspace{0.17em}Property\hspace{0.17em}\hspace{0.17em}of\hspace{0.17em}\hspace{0.17em}Multiplication)}\\ =180·20=3600\end{array}$

Thus, the value of the expression is$5·x^2·y=3600$.