Question

the midpoint of AB is M=(1,3). one endpoint is A=(4,1). find the coordinates of the other endpoint, b.

Answer 1

`~~~~~~~~~~~~\textit{middle point of 2 points } \\\\ A(\stackrel{x_1}{4}~,~\stackrel{y_1}{1})\qquad B(\stackrel{x_2}{x}~,~\stackrel{y_2}{y}) \qquad \left(\cfrac{ x_2 + x_1}{2}~~~ ,~~~ \cfrac{ y_2 + y_1}{2} \right) \\\\\\ \left(\cfrac{ x +4}{2}~~~ ,~~~ \cfrac{ y +1}{2} \right) ~~ = ~~\stackrel{\textit{\LARGE M}}{(1~~,~~3)} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{ x +4}{2}=1\implies x+4=2\implies \boxed{x=-2} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{ y +1}{2}=3\implies y+1=6\implies \boxed{y=5}`