Hi Kayleigh G
In Slope Intercept Form y = mx + b
Use the coordinates of the points given to calculate the slope m, then solve for b
Where
m=(y2 -y1)/(x2 - x1)
Then use one of the given coordinates to solve for b to get your first line
The perpendicular bisector will have an inverse slope of the opposite sign and pass through the coordinates of the midpoint of (1,8) and (5, -6)
Midpoint = ((x1 + x2)/2, (y1 + y2)/2)
Midpoint = ((1+5)/2, (8+(-6))/2 = (3,1)
y=(2/7)x + 1/7
You can graph your lines to confirm that are perpendicular and the perpendicular passes through the center coordinates, at Desmos.com.
I hope this helps