Answer:
-3n²+n³
Explanation:
Since the unknown number is n;
Product of the number and negative three is -3n
square of the number is n²
Taking their sum;
Sum = -3n + n²
Hence the sum of the product of the number and negative three and the square of the number is -3n+n²
If a number n is multiplied by the sum of the product of the number and negative three and the square of the number, hence the required function is;
f(n) = n(-3n + n²)
Expand
f(n) = -3n²+n³
This gives the required function