How Do You Find the X-Coordinate of a Point on a Line If You Have Another Point and the Slope?

The slope is the difference of our two y-values divided by the difference of our x-values
We can label the x- and y-coordinates of our points so we know how to plug them into the slope
Plug 2 in for the slope, and then plug our points into the x's and y's
After multiplying the equation by r we get: 2r=6
When we divide by 2, the left side is just r, and the right hand side is 6/2 which is 3

1. r is the missing x-coordinate in one of the ordered pairs on the line
1. 'Change' means the difference between the two y's or the two x's
1. The 1 and 2 subscripts are just place holders that tell us which point the y or x comes from
2. So we can make (x₁,y₁) equal to (0,-2) and (x₂,y₂) equal to (r,4)
1. Now we'll be able to plug 0 in for x₁ and 2 in for y₁
1. We'll be able to plug r in for x₂ and 4 in for y₂
1. Since we've labeled our points (0,-2) and (r,4), we can plug them into the right hand side
1. Based on how we labeled our points:
2. 0 is plugged in for x₁
3. -2 is plugged in for y₁
4. r is plugged in for x₂
5. 4 is plugged in for y₂
1. Simplify the fraction first by subtracting on the top and bottom
1. After multiplying by r we get: 2r=6
2. When we divide by 2, the left side is just r, and the right hand side is 6/2 which is 3
1. Remember, r was our missing x-coordinate

Find the value of r for the line with slope 2 that passes through the points (0,-2) and (r,4).