In a triangle the midline joining the midpoints of two sides is parallel to the third side and half as long ⇒ AС = 2*MN 3x + 10 = 2(x+5) 3x + 10 = 2x + 10 3x - 2x = 10 - 10 x = 0
M is a midpoint of AB ⇒ AM = BM 3y - 8 = 2(y+1) 3y - 8 = 2y + 2 3y - 2y = 2 + 8 y = 10