Question

A line intersects the points (3,-4) and (1,2) what is the slope intercept equation for this line

Answer 1

y=-3x+5

Explanation:

m=(y2-y1)/(x2-x1)

m=(2-(-4))/(1-3)

m=(2+4)/-2

m=6/-2

m=-3

y-y1=m(x-x1)

y-(-4)=-3(x-3)

y+4=-3(x-3)

y=-3x+9-4

y=-3x+5

Answer 2

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 = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (3, - 4) and (x₂, y₂ ) = (1, 2)

m =
`(2+4)/(1-3)` =
`(6)/(-2)` = - 3, thus

y = - 3x + c ← is the partial equation

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

Using (1, 2), then

2 = - 3 + c ⇒ c = 2 + 3 = 5

y = - 3x + 5 ← equation of line