I'm trying to get a cubic function from the points (0, 7), (2, 10), (4, 5), and (6, 0). I know the equation is y = ax^3 + bx^2 + cx + d, and

d = 7

After plugging in the other points I got 3 equations:

8a + 4b + 2c = 3

64a + 16b + 4c = -2

216a + 36b + 6c = -7

My substitution and elimination between three unknowns is more than shabby, could someone please help out?