Question

What is the equation of the function that is graphed as line b?

y = -2 x - 1
y = 1/2x + 1
y = 3 x
y = 2 x - 1

Answer 1

A

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, 1) and (x₂, y₂ ) = (0, - 1) ← 2 points on the line

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

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

y = - 2x - 1 ← equation of line b