Completely Factor the expression -18 P - 9

This question is off-topic, but I'm answering it assuming you meant to categorize as maths.

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Explanation:

Factoring

It consists of converting an algebraic expression, usually as a polynomial into two or more factored terms.

We must find the greatest possible common factor and use it to modify the original expression.

The given expression is

It's evident that both terms have a numeric common factor of -9. Let's factor by -9. We must divide each term by -9 to get:

We can even factor further by writing