SLOPE-INTERCEPT FORM
Math 8
Vocabulary
Slope
- a number that describes the direction and steepness of a line
change in y’s
change in x’s
y-intercept
- the point where a line crosses the y-axis
- denoted by the letter b
- it is the y-coordinate where the x-coordinate is 0
Vocabulary
Slope-intercept Form
- one form that the equation of a line can take, shows slope m and y-intercept b
- the x and y in the equation is any (x,y) point that makes the equation true, and therefore is on that line
- quick way to graph is to begin with the dot on the y-axis and then move
according to the slope to graph subsequent points, then connect them to form a line
Identify the slope and the y-intercept for the graph below. Show how the slope and y-intercept are connected to the equation.
Identify the slope and the y-intercept for the graph below. Show how the slope and y-intercept are connected to the equation.
Identify the slope and the y-intercept for the graph below. Show how the slope and y-intercept are connected to the equation.
Identify the slope (m), y-intercept (b) and then graph the equation.
Hints for graphing:
- placing more dots on the graph will get a better line
- up 2 units and right 3 units is the same as moving
down 2 units and left 3 units
- draw arrows at the end of the line, it will continue off the grid
begin
move
Identify the slope (m), y-intercept (b) and then graph the equation.
begin
move
Identify the slope (m), y-intercept (b) and then graph the equation.
begin
move
Given the graph, identify the slope (m), y-intercept (b) and write the equation of the line in slope-intercept form (y = mx +b).
Given the graph, identify the slope (m), y-intercept (b) and write the equation of the line in slope-intercept form (y = mx +b).
Given the graph, identify the slope (m), y-intercept (b) and write the equation of the line in slope-intercept form (y = mx +b).
Horizontal lines do fit in slope-intercept form,
but the slope of 0 becomes invisible and we just
see that every y-coordinate on the line is the same
Given the table, identify the slope (m), y-intercept (b) and write the equation of the line in slope-intercept form (y = mx +b).
x | y |
–3 | 5 |
–1 | 1 |
0 | –1 |
3 | –7 |
+ 2
+ 1
+ 3
−4
−2
−6
Given the table, identify the slope (m), y-intercept (b) and write the equation of the line in slope-intercept form (y = mx +b).
x | y |
4 | 8 |
4 | 0 |
4 | –3 |
4 | –10 |
+ 0
+ 0
+ 0
−8
−3
−7
There is no x coordinate
of 0 to look across from
When graphed this makes a vertical line
Vertical lines do have equations, but
they don’t work in slope-intercept form
Liam is reading a 254-page book for school. He can read 40 pages in one hour.
The equation for the number pages he has left to read is ,
where x is the number of hours he reads.
State the slope and the y-intercept.
Graph the equation
Interpret what the slope and the y-intercept
represent
The slope of −40 shows that the number of pages Liam has left to read is decreasing by 40 pages per hour
The y-intercept of 254 shows that at 0 hours Liam has 254 pages left to read (the total length of the book)
Time Spent Reading (hours)
Pages Remaining to Read