Question

Find the equation of the line passing through the coordinates ( 1 , 8) and ( 3, 18).

Answer 1

Answer:

y = 5x + 3

Step-by-step explanation:

First we need to find the slope.

The equation to find the slope is m = y2 - y1/x2 - x1  -----> (x1 and x2 just mean the x coordinate for the 2 points, so basically in this case, x1 would be 1 and x2 would be 3. Same for y1 and y2, just the y coordination of each point. y1 = 8 and y2 = 18)

m = 18 - 8/ 3 - 1

m = 10/2

m = 5

The slope would be 2 or 2/1. If you have a fraction that does not divide evenly, such as 3/5, DO NOT simplify unless specified.

Now that we have the slope, we can put this into point-slope form. The formula for this form is:

y - y1 = m(x - x1)

For this you would have to choose one of your points.

I'm going to choose the first one.

y - 8 = 5(x - 1) ----> Always remember in this formula the "m" is the slope, and we previously found out that it was 2, so plug 2 into m

From here just do basic multiplication and addition/subtraction.

y - 8 = 5x - 5

  +8          +8

y = 5x + 3

To test to see if these go through your points, plug the 2 points and equation into a website called desmos. (Very good site, and if your teacher has not recommend it, I highly advise using it. )