Answer :

Sure! Let's work through the expression step-by-step and simplify it.

Given the expression:
[tex]\[ (9 - x^2)(100 - y^2) - 120xy \][/tex]

First, let's expand the product [tex]\((9 - x^2)(100 - y^2)\)[/tex]:
[tex]\[ (9 - x^2)(100 - y^2) = 9 \cdot 100 + 9 \cdot (-y^2) + (-x^2) \cdot 100 + (-x^2) \cdot (-y^2) \][/tex]

This simplifies to:
[tex]\[ 9 \cdot 100 + 9 \cdot (-y^2) + (-x^2) \cdot 100 + (-x^2) \cdot (-y^2) = 900 - 9y^2 - 100x^2 + x^2y^2 \][/tex]

So,
[tex]\[ (9 - x^2)(100 - y^2) = 900 - 9y^2 - 100x^2 + x^2y^2 \][/tex]

Now, we need to subtract [tex]\(120xy\)[/tex] from this result:
[tex]\[ 900 - 9y^2 - 100x^2 + x^2y^2 - 120xy \][/tex]

Thus, the simplified form of the given expression is:
[tex]\[ -120xy + (9 - x^2)(100 - y^2) \][/tex]

In its expanded form:
[tex]\[ 900 - 9y^2 - 100x^2 + x^2y^2 - 120xy \][/tex]

So, the final expression is:
[tex]\[ -120xy + (9 - x^2)(100 - y^2) \][/tex]

This concludes the step-by-step simplification of the given expression.