Question

What is the equation of the blue line?

Answer 1

Y=-3x-1

I think that’s right

Answer 2

y = - 3x - 1

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 =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

with (x₁, y₁ ) = (- 1, 2) and (x₂, y₂ ) = (0, - 1)

m =
`(-1-2)/(0-(-1))` =
`(-3)/(0+1)` =
`(-3)/(1)` = - 3

the line crosses the y- axis at (0, - 1 ) ⇒ c = - 1

y = - 3x - 1 ← equation of line