Answer: y = 9
Explanation:
We see that both of the given coordinate points have the same y-value. This means that this line does not have a slope and is simply y = 9.
To confirm our answer, we can use the slope formula. This finds the change in y over the change in x. This gives us a slope of 0.
![\displaystyle (y_(2) -y_(1) )/(x_(2) -x_(1) ) =(9-9)/(-2-15)=0](https://img.qammunity.org/2022/formulas/mathematics/middle-school/2opccxv7n4sdqbqz5dqdccjjuo7l9ftouw.png)