Recall the relationship between the dividend, divisor, quotient, and remainder.

When a polynomial $f(x)$ is divided by a divisor $D(x)$, resulting in a quotient $Q(x)$ and a remainder $R(x)$, the relationship is given by:

$$f(x) = D(x) \cdot Q(x) + R(x)$$

Given:
Divisor $D(x) = x+2$
Quotient $Q(x) = x^2+x-1$
Remainder $R(x) = 3$
Substitute these into the formula:

$$f(x) = (x+2)(x^2+x-1) + 3$$

Multiply $(x+2)$ by $(x^2+x-1)$:

$$f(x) = x(x^2+x-1) + 2(x^2+x-1) + 3$$ $$f(x) = (x^3+x^2-x) + (2x^2+2x-2) + 3$$

$$f(x) = x^3 + (x^2+2x^2) + (-x+2x) + (-2+3)$$ $$f(x) = x^3 + 3x^2 + x + 1$$

The polynomial $f(x)$ is: