To find the length and width of the rectangle based on the area given, we first need to factor the expression for the area, which is \( x^2 + 7x + 12 \).
We will factor the quadratic expression:
- Look for two numbers that multiply to \( 12 \) (the constant term) and add up to \( 7 \) (the coefficient of \( x \)).
- The numbers \( 3 \) and \( 4 \) satisfy this condition since \( 3 \cdot 4 = 12 \) and \( 3 + 4 = 7 \).
Now we can write the factored form of the expression:
\[ x^2 + 7x + 12 = (x + 3)(x + 4) \]
Thus, the length and width of the rectangle can be represented as:
Length: \( x + 4 \)
Width: \( x + 3 \)
So, the correct choice from the multiple choice answers is:
\[ \text{(x + 3)(x + 4)} \]