A = (1, 5)
B = (2, 2)
C = (3, 0)
ax: x(A)
ay: y(A)
bx: x(B)
by: y(B)
cx: x(C)
cy: y(C)
nn: ax * (cx^(2.0) - bx^(2.0)) - bx * cx^(2.0) + bx^(2.0) * cx + ax^(2.0) * (bx - cx)
a: (ax * (cy - by) - bx * cy + by * cx + ay * (bx - cx)) / nn
b: -(ax^(2.0) * (cy - by) - bx^(2.0) * cy + by * cx^(2.0) + ay * (bx^(2.0) - cx^(2.0))) / nn
c: (ax * (by * cx^(2.0) - bx^(2.0) * cy) + ax^(2.0) * (bx * cy - by * cx) + ay * (bx^(2.0) * cx - bx * cx^(2.0))) / nn
f(x) = a * x^(2.0) + b * x + c
Text1: "f(x) = " + a + "x² + " + b + "x + " + c