Solve the equation. |k + 7| = 3 a. {–4, 10} b. {–10, –4} c. {–4, 4} d. {all real numbers greater than or equal to –10 and less than or equal to – 4}

The absolute value sign makes it so that k+7 could be either -3 or +3 and the result would still be 3. This means there are two possible answers for k. The one that makes k+7=-3 and the one that makes k+7=+3. Just solve these two equations:
k+7=-3
k=-3-7
k=-10

k+7=3
k=3-7
k=-4

So the possible answers are -4 and -10. B is the correct choice.