Question

Select the equation that contains the points (-1,-8) and (3,4)

Answer 1

y = 3x - 5

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, - 8 ) and (x₂, y₂ ) = (3, 4 )

m =
`(4-(-8))/(3-(-1))` =
`(4+8)/(3+1)` =
`(12)/(4)` = 3 , then

y = 3x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (3, 4 ) , then

4 = 9 + c ⇒ c = 4 - 9 = - 5

y = 3x - 5 ← equation containing the 2 points

Answer 2

it would help if we were given the equations to choose from ^^'