Answer:
[tex](x-5)(x+4)[/tex]
Step-by-step explanation:
To factor the equation, break it into two binomials which multiply to make the equation. To write these binomials (x+a)(x+b), find factors which multiply to -20 and add to -1 for a and b.
20: 1, 2, 4, 5, 10, 20
-5+4 = -1
[tex]x^2-x-20 = (x-5)(x+4)[/tex]