Answer:
(x + 3)(x + 4)
Explanation:
To factor the trinomial
Consider the factors of the constant term ( + 12) which sum to give the coefficient of the x- term ( + 7)
The factors are + 3 and + 4, since
3 × 4 = 12 and 3 + 4 = 7, hence
x² + 7x + 12 = (x + 3)(x + 4)
Thus length can be x + 3 or x + 4 and
the width can be x + 4 or x + 3