Another approach:
Now you can expand the polynomial.
Find a degree 3 polynomial with zeros -2, 1, and 5 going through the point [0, -3].
This is what I have so far:
y=ax^3 + bx^2 + cx + d
0=-8a + 4b - 2c + d
0= a + b + c + d
0= 125a + 25b + 5c + d
-3= 0a + 0b + 0c + d
d= -3
So how do I solve this system now?
Any help is greatly appreciated.