Answer: [tex](x-5)[/tex]
Step-by-step explanation:
The given expression : [tex]\frac{3x-15}{x^2-x-20}[/tex] [Taking as common outside]
[tex]\text{Polynomial in numerator=}3x-15=3(x-5)[/tex]
[tex]\text{Polynomial in denominator=} x^2-x-20\\\\=x^2-5x+4x-20\\=-x(x-5)+4(x-5)\\=(x-5)(x+4)[/tex]
We can see that the greatest common factor (GCF) of the numerator and denominator of given the rational expression = [tex](x-5)[/tex]