AB is divided into 8 equal parts and point C is 1 part FROM A TO B, so the ratio is 1:7, with C being 1/7 of the way. The ratio is k, found by writing the numerator of the ratio (1) over the sum of the numerator and denominator (1+7). So our k value is 1/8. Now we need to find the rise and the run (slope) of the points A and B. 
. That gives us a rise of -4 and a run of 12. The coordinates of C are found in this formula: ![C(x,y)=[ x_{1} +k(run), y_{1} +k(rise)]](https://tex.z-dn.net/?f=C%28x%2Cy%29%3D%5B%20x_%7B1%7D%20%2Bk%28run%29%2C%20y_%7B1%7D%20%2Bk%28rise%29%5D)
. Filling in accordingly, we have ![C(x,y)=[-3+ \frac{1}{8}(12),9+ \frac{1}{8}(-4)]](https://tex.z-dn.net/?f=C%28x%2Cy%29%3D%5B-3%2B%20%5Cfrac%7B1%7D%7B8%7D%2812%29%2C9%2B%20%5Cfrac%7B1%7D%7B8%7D%28-4%29%5D%20%20)
which simplifies a bit to 
. Finding common denominators and doing the math gives us that the coordinates of point C are 
. There you go!