Question 1125392
Let the other end point = ( a,b )
M( 5,7 )
( 3,-5 )
覧覧覧-
 {{{ ( a + 3 )/2 = 5 }}}
{{{ a + 3 = 10 }}}
{{{ a= 7 }}}
覧覧覧-
{{{ ( b +(-5) )/2 = 7 }}}
{{{ b - 5 = 14 }}}
{{{ b = 19 }}}
The other end point is ( 7,19 )