Find the coordinates of the point 7/10 of the way from A to B
A (-4, -5)
B (12,4)

The trick it to separate the 7/10 relating to the x-coordinates from the 7/10 relating to the y-coordinates.

For the x-coordinate:

You need to find the difference in the x-values

    12-(-4) = 16

and then find 7/10 of that and add it to the starting x-coordinate (the x-coordinate of Point A).

For the y-coordinate:

You need to find the difference in the y-values

    4-(-5) = 9

and then find 7/10 of that and add it to the starting y-coordinate (the y-coordinate of Point A).

Can you take it from there?