i am homeschooled and i use khan academy and I CAN NOT GET THESE TYPES OF QUESTIONS AT ALL

i am homeschooled and i use khan academy and I CAN NOT GET THESE TYPES OF QUESTIONS AT ALL

A
B, and 
C are collinear, and 
B is between 
A and 
C. The ratio of 
AB to 
AC is 
1:4.

If A is at (−7,−8) and B is at (−3,−5), what are the coordinates of point C?