Question

Sendo M (1,-4) o ponto médio de AB e A (3,5), determine as coordenadas do ponto B.

Answer 1

M(1,-4)
A(3,5)

xm = ( xa + xb ) / 2

1 = ( 3 + xb ) / 2

2 = 3 + xb

xb = -1

ym = ( ya + yb ) / 2 

-4 = ( 5 + yb ) / 2

-8 = 5 + yb

yb = -13

B(-1,-13)