1. POINTS AND LINES ON THE COORDINATE PLANE

2. SLOPE OF A LINEAR FUNCTION
It is always constant
Rate of change of y with respect to x.

3. Finding Equations of Lines
Given a point and a slope – Find the equation of the line given A(2, 5) on the line and that the line has a slope of -3.
You can use either….
y = mx + b form or y - y1 = m(x – x1) form
In the first equation m is the slope and b is the y-intercept
In the 2nd equation m is the slope and (x1, y1) is a point.

4. Finding Equations of Lines
Given a point and a slope – Find the equation of the line given A(2, 5) on the line and that the line has a slope of -3.
Which do you think is a better choice?
y - y1 = m(x – x1) form because you are given the slope and a point!
Substitute in values: y - 5 = -3(x – 2) done!

5. Finding Equations of Lines
Given 2 points - Find the equation of the line passing through points A(3, 6) and B(1, -5).
Find slope first. Then repeat the process from the previous example!
y - 6 = 5.5(x – 3)

6. Graphing a Line – What is the best method?
y = 2x + 1
(Since this equation is in
slope intercept form, use
slope/intercept)
y + 1 = 2(x + 1)
(Use slope and point since its
point/slope form)
(produces the same line!)
y = 2x + 2
(in slope/intercept,
but y-intercept irrational
substitute values to get 2 points)
2x + 4y = 5
(Find x and y intercepts
x = 0  y-intercept
y = 0  x-intercept)

7. Vertical and Horizontal Lines
Horizontal lines have an equation of the form y = b where ‘b’ is the y-coordinate of any point on the line. Any horizontal line has a slope of 0.
Vertical lines have an equation of the form x = a where ‘a’ is the x-coordinate of any point on the line. The slope is undefined for any vertical line.

8. Parallel and Perpendicular Lines
the same!
The slopes of parallel lines are __________.
The slopes of perpendicular lines are ______________________________________.
Find the equation of the line passing through (3, 1) and perpendicular to y = 4x – 2.
opposite and reciprocal!
y - 1= -.25(x – 3)

9. perpendicular
vertical
collinear
horizontal
parallel
reciprocal
slope
intercept
linear