Question 936203
(1,1)
(7,1) M = (4, 1)
x = 4 represents the locus of points equidistant from points (1,1) and (7,1)
{{{drawing(300,300, -10, 10, -10, 10,  grid(1),blue(line(4,10,4,-10)),  
circle(1, 1,0.4),
circle(7, 1,0.4),
circle(4, 1,0.4),
graph( 300, 300,  -10, 10, -10, 10))}}}