Line PT contains the points (9,-3) and (0,15). What is the equation

Question

Having trouble on everything 

Answer 1

Jordan,

 

The general equation you're looking for is:

 

(y - y₁) = m(x - x₁) where m is the slope and (x₁,y₁) is one of the points on the line.

 

First, you need to find the slope:

 

m = (y₂ - y₁)/(x₂ - x₁)

 

Substituting the two points we know:

 

m = (15 - (-3))/(0 - 9) = 18/-9 = -2 (slope)

 

Then, picking one of the points on the line (let's do the second), we get:

 

y - 15 = -2(x - 0)

 

y - 15 = -2x

 

y = -2x + 15 which is our line.

 

Hope this helps!

Answer 2

SLOPE FORMULA:

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


Let (9,-3) be point 1
Let (0,15) be point 2

m = (15 - -3)/(0 - 9)

m = 18/(-9)

m = -2

 

Then use one of the points (0,15) and the slope, of the line, to find the equation

 

y - y₁ = m(x - x₁)

 

y - 15 = -2(x - 0)

 

y = -2x + 15