What are the equations for a lines with the points of -2 and-4 and 4 and-1?

Answer 1

Assuming you want the equation of a straight line through (-2, -4) and (4, -1):

y - y0 = m(x - x0) where m = (y1 - yo) ÷ (x1 - x0)

⇒ y - (-4) = (-1 - (-4))/(4 - (-2))(x - (-2))

⇒ y + 4 = 3/6 (x + 2)

⇒ y = x/2 - 3

or 2y = x - 6

Equations of higher order (eq quadratics) have infinitely many equations.