i've this problem as a homework plz help me to answer it!?

Question

ABC is a triangle M & N are two points on this triangle; locate these points through this equations vactor AM = 1/2 vactor AB - vactor AC
& vactor AN = - vactor AB + 1/2 AC

Answer 1

go to math.com or something and they will show you how to solve it so you learn the method

Answer 2

1/2 vector AB - vector AC would put the point M outside the triangle which contradicts your statement that it is on the triangle.

-1/2 vector AB + 1/2 vector AC puts the point N at the midpoint of vector AC.