a) What is the number which gives midpoints of the points denoted by the numbers `x` and `y` on the number line.
b) If the numbers `x` and `y` are thought of as points on a number line, what is the geometrical meaning of `|x-y| ?`
c) .Find those `x` satisfying each of the equations below.
i) `|x-1|=|x-3|`
ii) `|x-1|=|x+3|`
ifi) `|x+1|=|x-3|`