1. Writing Linear Equations
EQ: How are equations of linear functions written?

2. Recall: What is slope-intercept form? y = mx + b
What two values do you use most in slope intercept form?
slope and y-intercept

3. To write an equation of a line given m and b…
Put m and b into slope intercept form: y = mx + b
Ex: Find the equation of a line whose slope is -2 and y intercept is 8.
m = -2 and b = 8
So…
y = -2x + 8
Note that x and y remain variables in the equation.

4. You try…..
Write the equation of a line whose slope is -3 and y intercept is -4.
y = -3x – 4
Write the equation of a line whose slope is ½ and y intercept is 0.
y = ½x
Write the equation of a line whose slope is 0 and y-intercept is -6.
y = -6

5. To write an equation of a line given slope and a point…
…use Slope-Intercept Form
y = mx + b

6. Using slope – intercept form
Substitute slope and the x and y values from the ordered pair into slope-intercept form to find b.
Then write the equation using m and b.
Ex: slope -1 and (2, -3)
y = mx + b
-3 = -1(2) + b
-3 = -2 + b
-1 = b
So…
y = -1x + -1

7. You try…
Write the equation of a line whose slope is ½ and contains the point (0, - 2)
y = ½x – 2
Write the equation of a line whose slope is -4 and contains the point (4, -1)
y = -4x + 15
Write the equation of a line whose slope is ¾ and contains the point (0, 0)
y = ¾x