Final answer:
To rewrite 15x^4y^3 - 45x^3y^4 using a common factor, factor out the greatest common factor (GCF) from each term.
Step-by-step explanation:
To rewrite 15x^4y^3 - 45x^3y^4 using a common factor, we can find the greatest common factor (GCF) of the terms. In this case, the GCF is 15x^3y^3. We can factor out the GCF from each term:
15x^4y^3 - 45x^3y^4 = 15x^3y^3(x - 3y).
So, the expression 15x^4y^3 - 45x^3y^4 can be rewritten as 15x^3y^3(x - 3y). This means that 15x^3y^3 is a common factor of the original expression.