Question

What is the equation of the line that passes through the points (2, -4) and (0, 8)?

A. y = 6 x + 8
B. y = 2 x + 8
C. y = -6 x + 8
D. y = -2 x + 8

(What about this one, please?)

Answer 1

C

Explanation:

the equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y-intercept )

To calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (2, - 4) and (x₂, y₂ ) = (0, 8)

m =
`(8+4)/(0-2)` =
`(12)/(-2)` = - 6

note the line passes through the point (0, 8) ⇒ c = 8

y = - 6x + 8 → C