To find the greatest common factor (GCF) of -25x^4-20x^3-20x^2, let's factor out the greatest common factor from each term.
The GCF of -25x^4, -20x^3, and -20x^2 is -5x^2, not just -5x^2.
Let's double-check our work:
-25x^4 can be factored as -5x^2 * 5x^2.
-20x^3 can be factored as -5x^2 * 4x.
-20x^2 can also be factored as -5x^2 * 4.
Therefore, the greatest common factor of -25x^4-20x^3-20x^2 is -5x^2. Well done!