1. Writing an Equation of a Line
       Determine the equation of a line and/or graph a linear equation.

2. Slope-intercept Form y = mx + b
any ordered pair (x,y)
Slope-intercept Form y = mx + b
Slope y-intercept

3. The method used to write an equation of a line depends
on the information about
the line that is available.

4. If given the slope and y-intercept,
slope-intercept form.
Example
m = 5, b = 7 5 7
y = ___ x + ___

5. If given a point and the slope,
Example
m = –2, contains (5, –8)
Step 1
Substitute –2 for m, 5 for x, and
–8 for y; then simplify to find
the value of b.
y = mx + b
–8 = –2(5) + b
–8 = –10 + b
2 = b
Step 2
Substitute –2 for m, and 2 for b.
y = –2x + 2

6. If given two points, First, find the slope using the slope formula.
Example
contains (5, –8) and (2, 7)
m = 15 –3
m = –5
m = 7 – -8
2 – 5

7. If given two points, continued
Then use the slope you just found and EITHER
point to work like the previous example.
y = -5x + b
7 = -5 (2) +b
7 = b
17 = b
m = –5,
contains (5, –8) and (2, 7)
y = –5x + 17

8. Parallel lines

9. you try Find the equation of each line using the given information.
m=2, y-intercept is -1
the line passes through the points (8, 2) and (12, 4)
the line is parallel to the line y = ⅔x + 4, and passes through the points (6, 7)