Find the slope and y-intercept of each line?

Question

1.)   Y=-x-4

 

 

 

2.) 2x+3y=-3

Answer 1

The slope intercept form of a linear equation is:

y = mx + b

In this form the slope = m, y-intercept is the point (0,b)

 

1.  y = -x - 4

 

     The slope is m = -1

 

     The y-intercept is found by setting x=0

     y = 0-4 = -4

     The y-intercept is the point (0,-4)

 

2.  2x + 3y = -3

 

     This line is in standard form of ax + by = c.

     If we put that into slope intercept form by solving for y we have:

     y = (-a/b) x + c/b

     The slope m = -a/b  and the y-intercept is the point (0, c/b)

     This is actually a formula you can use to plug in for any equation

     of the form ax + by = c to find slope and y-intercept.

 

     m = -a/b = -2/3

     y-intercept = (0, -3/3) = (0, -1)

 

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The above is the way to look at it logically and avoid the calculations

in solving for y first.  If that is confusing then solve your equation for y:

 

2x + 3y = -3

3y = -2x-3

y = (-2x-3)/3

y = (-2/3)x -1

 

m = -2/3

y-intercept = (0,-1)