_{1})/(x-x

_{1})

_{1})=m(x-x

_{1})

**y=2.5x+0.5**

find the equation of the line containing the given points (1,3) and (-3,-7). Express your answer in slope-intercept form.

Tutors, sign in to answer this question.

Hi Grace;

(1,3) and (-3,-7)

The slope is defined as the change-of-y divided by the change-of-x...

(y-y_{1})/(x-x_{1})

(3--7)/(1--3)

Subtracting a negative number is the same as adding a positive number...

(3+7)/(1+3)

10/4

2.5

Let's take one point and apply the point-slope formula. This will expand into the slope-intercept formula. I randomly select the first point...

(y-y_{1})=m(x-x_{1})

(y-3)=2.5(x-1)

y-3=2.5x-2.5

Let's add 3 to both sides...

3+y-3=2.5x-2.5+3

This is slope-intercept format of...

y=mx+b, m is the slope and b is the y-intercept, the value of y when x=0.

Let's plug-in the other point to verify formula...

-7=[2.5(-3)]+0.5

-7=-7.5+0.5

-7=-7

Hafid M. | Experienced Science and Math TutorExperienced Science and Math Tutor

Slope intercept form is the form y= mx+b

where m is the slope and b is the y-intercept.

First, find your slope and plug into the form above

slope can be remembered as "rise over run." and your "rise" will be Y2-Y2 or 3-(-7) = 10

the "run" will be X2- X1 or 1 - (-3) = 4

therefore the slope is (Y2 - Y1 ) / (X2 - X1) = 10/4 or 2.5

Now plug into the slope intercept form using either of your original points. I picked the point (1,3)

y = mx + b

3 = (2.5)(1) + b now you must solve for b

3 = 2.5 + b and b = 0.5

Therefore the equation of the line is y = 2.5x + 0.5

Already have an account? Log in

By signing up, I agree to Wyzant’s terms of use and privacy policy.

Or

To present the tutors that are the best fit for you, we’ll need your ZIP code.

Your Facebook email address is associated with a Wyzant tutor account. Please use a different email address to create a new student account.

Good news! It looks like you already have an account registered with the email address **you provided**.

It looks like this is your first time here. Welcome!

To present the tutors that are the best fit for you, we’ll need your ZIP code.

Please try again, our system had a problem processing your request.

## Comments

_{1}or y_{2}. Your equation for slope is correct. It will produce the result of -10/-4 which is 10/4 which is 2.5. This is the same result we reached.