Notes on Slope-Intercept Form

Essential Question: What does the slope of a line indicate about the line?

Benchmark: “The student will be able to…” Determine the slope, x-intercept and y-intercept of a line given its graph, its equation, or two points on the line.

Learning Goal: “The student will be able to understand…” Use coordinate geometry to find slopes, parallel lines, perpendicular lines, and equations of lines.

Learning Activity: “We will learn this by…”

Notes on Slope-Intercept Form

Slope-Intercept Form is an equation written in the form:

y = mx + bm = slope and b = y-intercept.

b = 7

m = 2

y = 2x + 7

b = -4

m = ½

y = ½x - 4 Write an equation of the line with a slope of 4 and y-intercept of -2.

y = 4x – 2

Write an equation of the line shown in the graph.

m =

Y2 – Y1

X2 – X1

m =

3 – (1)0 – 2

m =

4

-2or -2

(0,3)

(2,-1)

y = mx + b

y = -2x + 3

b = 3

m =

Y2 – Y1X2 – X1

m =

4 – (-4)-1 – 3

m =

(-1,4)(3,-4)

y = mx + b

y = -2x + b

Write in Slope-Intercept form and identify the slope and y-int

x1 y1 x2 y2

Steps:

1st – Calculate the slope

2nd – Plug in either point to get the value of “b”

4 + 4-1 + (-3)

m =

8-4

= -2

-4 = -2(3) + b-4 = -6 +

b+6 +62 = b

y = -2x + 2

m =

Y2 – Y1X2 – X1

m =

-5 – 1-1 – 5

m =

(-1,-5)

(5,1)

y = mx + b

y = x + b

Write in Slope-Intercept form and identify the slope and y-int

x1 y1 x2 y2

Steps:

1st – Calculate the slope

2nd – Plug in either point to get the value of “b”

-5 + (-1)-1 + (-5)

m =

-6-6

= 1

5 = 1 + b-1 -

14 = b

y = x + 4

y = mx + b

5x – 3y = 6

Graph 5x - 3y = 6

-5x -5x

-3y = -5x + 6-3 -3

y = x - 253

(3,3)

(0,-2)

y = mx + b

2x + y = 3

-2x -2x

y = -2x + 3

Write in Slope-Intercept form and identify the slope and y-int

b = 3

m = 2

y = mx + b

6x + 3y = -9-6x -6x

3y = -6x - 93 3

y = -2x - 9

b = -9

m = -2

y = mx + b

12x – 3y = 6-12x -12x

-3y = -12x + 6-3 -3

y = 4x - 2

b = -2

m = 4