• a) Given the points:
(x1, y1) ==> (k, 2)
(x2, y2) ==> (11, 14)
Slope, m = 2
To find the missing coordinate, k, use the slope formula below:
![m=(y2-y1)/(x2-x1)](https://img.qammunity.org/2023/formulas/mathematics/high-school/wt3vklmulg2853jxzclws9uvfaplhmpgv7.png)
Input values into the formula to find k:
![2=(14-2)/(11-k)](https://img.qammunity.org/2023/formulas/mathematics/college/jr4oje5yt3c5gd97eq9ddg46xykw0kja2j.png)
Let's solve for k.
Cross multiply:
![\begin{gathered} 2(11-k)=14-2 \\ \\ 22-2k=14-2 \\ \\ -2k=14-2-22 \\ \\ -2k=-10 \\ \\ (-2k)/(-2)=(-10)/(-2) \\ \\ k=5 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/pftnue940jz0rl4ib45eltfnhnfr0ceh5g.png)
b) Given the points:
(x1, y1) ==> (1, k)
(x2, y2) ==> (4, 1)
slope = -2
Let's use the method in question (a) to find k:
![\begin{gathered} -2=(1-k)/(4-1) \\ \\ -2(4-1)=1-k \\ \\ -8+2=1-k \\ \\ -8+2-1=-k \\ \\ -7=-k \\ \\ k=7 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/n6ozukfcgbraoizl33199ata3no2rd4u1m.png)
c) Given the points:
(x1, y1) ==> (3, 5)
(x2, y2) ==> (k, 9)
slope = 1/2
Let's use the method above to solve for k:
![\begin{gathered} (1)/(2)=(9-5)/(k-3) \\ \\ 1(k-3)=2(9-5) \\ \\ k-3=18-10 \\ \\ k=18-10+3 \\ \\ k=11 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/fpvhczbrn7ah0w5i8odo3x9lygtff643jp.png)
d) Given the points:
(x1, y1) ==> (-1, 4)
(x2, y2) ==> (-3, k)
slope = -1/2
Solve for k:
![\begin{gathered} -(1)/(2)=(k-4)/(-3--1) \\ \\ -(1)/(2)=(k-4)/(-3+1) \\ \\ 2(k-4)=-1(-3+1) \\ \\ 2k-8=3-1 \\ \\ 2k-8=2 \\ \\ 2k-8+8=2+8 \\ \\ 2k=10 \\ \\ (2k)/(2)=(10)/(2) \\ \\ k=5 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/lzxttnyznq4me7rqsq3ptrjdsjqfeu4da0.png)
ANSWER:
a) k = 5
b) k = 7
c) k = 11
d) k = 5