parabola find the equation

Question

The equation for a parabola has the form y = ax^2 + bx + c, where a, b, and c are constants and a≠0. Find an equation for the parabola that passes through the points (−1,−9), (−3,1), and (3,19).

y = ?????

Answer 1

-9 = a(-1)² + (-1)b + c

1 = a(3)² + (-3)b + c

9 = a(3)² + 3(b) + c

Solve the system and answer. Use Algebra 2 techniques.