Answer:
y = -
x
Explanation:
the equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
calculate m using the slope formula
m =

with (x₁, y₁ ) = (0, 0) and (x₂, y₂ ) = (50, - 10) ← 2 points on the line
m =
=
= -

the line crosses the y- axis at (0, 0 ) ⇒ c = 0
y = -
x + 0 , that is
y = -
x ← equation of line