Question

A(-3,2) B(5,-4) midpoint is (1,-1)

Answer 1

$CHECK:\\\\the\ midpoint\ AB:\left(\frac{-3+5}{2};\ \frac{2-4}{2}\right)=\left(\frac{2}{2};\ \frac{-2}{2}\right)=(1;-1)\\-------------------------------\\C(x;\ y)\\\\the\ midpoint\ AC:\left(\frac{-3+x}{2};\ \frac{2+y}{2}\right)\\\\B\ is\ the\ midpoint\ AC\ then:\\\\\frac{-3+x}{2}=5\ and\ \frac{2+y}{2}=-4\\\\-3+x=10\ and\ 2+y=-8\\\\x=10+3\ and\ y=-8-2\\\\x=13\ and\ y=-10\\\\Solution:C(13;-10).$