Question

Which is an equation of the line that passes through (-1,-5) and (-3,-7)

Answer 1

y = x - 4

correct answer

Explanation:

Answer 2

Slope intercept formula is:

y = mx + b

m is the slope

b is the y-intercept

Let's find m, the slope:

The formula for slope when using two points on a line is:

`(y_(2)-y_(1))/(x_(2)-x_(1))`

In this case...

`y_(2) =-7\\y_(1) =-5\\x_(2) =-3\\x_(1) =-1`

^^^Plug these numbers into the formula for slope...

`(-7-(-5))/(-3-(-1))`

`(-2)/(-2)`

1

^^^This is your slope

So far this is our equation:

y = 1x + b OR y = x + b

Now let's find b, the y-intercept:

To do that you must plug in the point the line goes through in the x and y of the equation.

For this question I have chosen to plug in the point (-1, -5)

-5 = -1 + b

-5 + 1 = -1 + 1 + b

-4 = 0 + b

-4 = b

Your equation is:

y = x - 4

Hope this helped!

~Just a girl in love with Shawn Mendes