### Home > CCA2 > Chapter 9 > Lesson 9.1.3 > Problem9-39

9-39.

What is the probability that $x^2 + 7x + k$ is factorable if $0 ≤ k ≤ 20$ and $k$ is an integer?

How many possible values are there for $k$? This is the denominator of the probability.

What numbers between $0$ and $20$ starting with $1$ and going to $20$ have two factors that add to $7$? Note: $0$ works because $x$ would be a factor.

$\frac{\text{Number of }k\text{s that work}}{\text{All possible }k\text{s}}$