Question

Point m is the midpoint of kL. M(1,-1) and L(8,-7. What are the coordinates of point k?

Answer 1

Answer: (-6, 5)

Step-by-step explanation:

Use the Midpoint Formula: $\dfrac{(x_k, y_k)+(x_L,y_L)}{2}=(x_m, y_m)$

Separate the x's and y's and solve them individually:

$\dfrac{x_k+x_L}{2}=x_m\qquad \qquad \qquad \qquad\dfrac{y_k+y_L}{2}=y_m\\\\\\\dfrac{x_k+8}{2}=1\qquad \qquad \qquad \qquad \qquad \dfrac{y_k-7}{2}=-1\\\\\\x_k+8=2\qquad \qquad \qquad \qquad \qquad y_k-7=-2\\\\\\x_k\quad =-6 \qquad \qquad \qquad \qquad \qquad y_k\qquad =5$

            So, the k-coordinate is (-6, 5)