(x_1,y_1)

(x_2,y_2)

f(x) = x^(2)
A = Point(f)
B = Point(f)
a = Line(B, A)
m: (y(B) - y(A)) / (x(B) - x(A))
b: y(A) - m * x(A)
X: x(A)
text1: " x=" + X + "
m=" + m + "
 b=" + b + ""