The
correct answer is:
x²+2x+3.
Explanation:

We need to divide each term of the numerator by the denominator. For the
first term:

Dividing the coefficients, we have 5/5 = 1.
When dividing the variables, we use the quotient rule: when dividing powers that have the same base, subtract the exponents. This gives us:
x³/x = x³/x¹ = x³⁻¹ = x²
For the first monomial, this gives us 1x² = x².
The
second term:

Dividing the coefficients, we have 10/5 = 2.
Dividing the variables, we again use the product rule:
x²/x = x²/x¹ = x²⁻¹ = x¹ = x
Together this gives us 2x.
The
third term:

Dividing the coefficients, we have
15/5 = 3.
Dividing the variables, we have x/x; when you divide something by itself, the answer is 1. This gives us:
3*1 = 3.
Together our quotient is x²+2x+3.