Question

A line passes through the points (20, 15) and (19, 14) What is its equation in slope-intercept form?

Answer 1

y = x-5

Explanation:

The form of slope intercept is y=mx+b]

To solve :

First you need to find the slope

To find the slope, you the slope equation, which is y2-y1/x2-x1

Since first you put y2-y1 at the top, it would be 14-15 and then 19-20 at the bottom since x2-x1 is put at the bottom.

Your slope equation should be : m=14-15/19-20, which should give you m=-1/-1 with m being 1.

Then you plug in the value in the slope intercept equation

To help us find the y intercepts, lets choose one our points. In this case, we will be using (20,15) since it is the first point.

Slope intercept form is y=mx+b.

we do 15= 1 x 20 +b

15=20+b, gives you b=-5

How you got b=-5:

1)Put the equation into this by switching sides :

1 (20)+b=15

2) Get rid of the parenthases :

1 x 20 + b=15

3) multiply :

1 x 20=20, so

20+b=15

4) On both sides, subtract 20

so it would be

20+b-20=15-20, which gives you b=-5

Answer 2

Answer: y = x - 5

Explanation:

Slope intercept form is y = mx + b

to find the slope: y2-y1/x2-x1: 15-14/20-19 = 1/1 = 1

so we can write it as y = x + b, (since the slope is 1).

To find b, plug in either point given to the formula:

15 = 20 + b

b = 15 - 20

b = -5

so the completed equation is y = x - 5