slope

Question

A line that includes the points (-1,s) and (3,10) has a slope of 5. What is the value of s?

Answer 1

To find s you need to know the slope-intercept form of a line. That looks like y=mx+b where m is the slope and b is the y-intercept. Now that you know that you can plug in the information you have for the first step.

 

You have x and y of one of your points and you have the slope so plugging those in looks like:

 

10=5(3)+b

 

10=15+b

 

-5=b

 

Now that you've solved for b you know the y-intercept for your line. Using that information and the other partial point you've been given you can plug in and find s. It looks like this:

 

s=5(-1)+ -5

 

Solve and you find s

 

s=-5 + -5

 

s= -10

Answer 2

5=m=(y2-y1)/(x2-x1)=(10-s)/(3+1)

5*4=10-s

20-10=-s

10=-s

s=-10

Answer 3

Given two points on a line, we can determine the slope by finding the difference of the y-coordinates divided by the difference of the x-coordinates. Using that, we can set up the following equation:

 

(10 - s)/(3 - (-1)) = 5

 

(10 - s)/4 = 5

 

10 - s = 20

 

-s = 10

 

s = -10