Answer:
8
Explanation:
The product of terms on the left of the equal sign is ...
(x+6)(x+k) = x^2 +(6+k)x +6k
So, you have two clues to the value of k. The coefficient of x must match, and the constant must match.
6+k = 14 ⇒ k = 8
6k = 48 ⇒ k = 8
The value of k is 8.