I Have Solved It But I Just Need Someone To Check It For Me Use Least Squares Ap

I have solved it but I just need someone to check it for me.

The solved problem is attached. 

Use least-squares approximation to find the best linear fit (i.e., the best line)

y = Ct + D

to the following data points:

(t1, y1)=(-3, -4)

(t2, y2) = (0, -7)

(t3, y3) = (3, -16).

What are the values of C and D that define this line?