Answer:
By long division (x³ + 7·x² + 12·x + 6) ÷ (x + 1) gives the expression;

Explanation:
The polynomial that is to be divided by long division is x³ + 7·x² + 12·x + 6
The polynomial that divides the given polynomial is x + 1
Therefore, we have;

(x³ + 7·x² + 12·x + 6) ÷ (x + 1) = x² + 5·x + 7 Remainder -1
Expressing the result in the form
, we have;