As GeoGebra allows us to calculate with vectors, this is an easy task.
A = (-2, 1) B = (3, 3) T = A + 7/10 (B - A)
Another way of doing this could be
A = (-2, 1) B = (3, 3) v = Vector[A, B] T = A + 7/10 v
In a next step we could introduce a number t (e.g. by using a slider, 3.2.10) and redefine the point T as T = A + t v (see 3.1.7). By changing t you can see T moving along a straight line.
This line could be entered now in parameter form (see 4.2.3):
g: X = T + s v