(3,-1)slope=-1

Question

I need help please I don't understand new math. Thanks

Answer 1

Hey Taylor,

 

Do you remember all the equations that involves a line?

 

y = mx + b (slope y-intercept)

 

m (x₁ - x₀) = (y₁ - y₀)  point-slope

 

Ax + By = C ---> standard (general) form

 

slope (m) = (y₁ - y₀) / (x₁ - x₀)

 

In this case, you have to use point-slope form.

 

m (x₁ - x₀) = (y₁ - y₀)

 

-1 (x₁ - 3) = (y₁ - (-1))

 

-1x+3 = y+1

 

-x+3 = y+1

 

So, here are two ways to write the equation of the given line:

 

y = -x+2   (slope y-intercept form)

x+y = 2   (standard form or general form)

 

I hope you got it.  Good luck to you.

 

Which form does your book (homework) want? which form does your teacher want?

 

 

Answer 2

The equation of a line is:

 

y = mx + b

 

Where m is the slope and b is the y-intercept (the point where the line crosses the y-axis).  To find the equation of a particular line, you need to find the values of m and b.  The problem gives you the value of the slope, m = -1.  So the equation of the line so far is:

 

y = -1x + b = -x + b

 

To find b, just plug in the value of the point given in the problem, (3,-1), and solve for b:

 

y = -x + b

-1 = -(3) + b         [Plugged in y = -1, x = 3]

2 = b

 

So the final equation of the line with slope = -1 that passes through the point (3,-1) is:

 

y = -x +2