We are given the points
(0,-4),(1,0),(2,2)
The standard form a quadratic function (in terms of x) is
y = Ax2 + Bx + C
Subsitute the points
-4 = 0 + 0 + C
C = -4
0 = A + B - 4
2 = 4A + 2B - 4
Solve for A and B
A = -1
B = 5
The function is
y = -x2 + 5x - 4