1. LT: I can graph and write equations of lines
Entry Task
LT: I can graph and write equations of lines

2. 2.3 Linear Functions and Slope-Intercept Form
Learning Target:
I can
Graph linear equations
I can write equations of lines.

3. LT: I can graph and write equations of lines
Review of Formulas
Formula for Slope
Point-Slope Form
Slope-intercept Form
Standard Form
*where A>0 and A, B, C are integers
LT: I can graph and write equations of lines

4. LT: I can graph and write equations of lines
Slope
LT: I can graph and write equations of lines

5. Examples of linear equations
2x + 4y =8
6y = 3 – x
x = 1
-2a + b = 5
Equation is in Ax + By =C form
Rewrite with both variables on left side …
x + 6y =3
B =0 … x + 0 y =1
Multiply both sides of the equation by -1 … 2a – b = -5
Multiply both sides of the equation by 3 … 4x –y =-21
LT: I can graph and write equations of lines

6. Examples of Nonlinear Equations
The following equations are NOT in the standard form of Ax + By =C:
The exponent is 2
There is a radical in the equation
Variables are multiplied
Variables are divided
4x2 + y = 5
xy + x = 5
s/r + r = 3
LT: I can graph and write equations of lines

7. LT: I can graph and write equations of lines
Find the slope of a line through points (3, 4) and (-1, 6).
LT: I can graph and write equations of lines

8. Write an equation for the line that passes through (-2, 5) and (1, 7):
Find the slope:
Use point-slope form:
LT: I can graph and write equations of lines

9. LT: I can graph and write equations of lines
Change into slope-intercept form and identify the slope and y-intercept.
LT: I can graph and write equations of lines

10. LT: I can graph and write equations of lines
Change into standard form.
LT: I can graph and write equations of lines

11. x-intercepts and y-intercepts
The intercept is the point(s) where the graph crosses the axis.
To find an intercept, set the other variable equal to zero.
LT: I can graph and write equations of lines

12. LT: I can graph and write equations of lines
Horizontal Lines
Slope is zero.
Equation form is y = #.
Write an equation of a line and graph it with zero slope and y-intercept of -2.
y = -2
Write an equation of a line and graph it that passes through (2, 4) and (-3, 4).
y = 4
LT: I can graph and write equations of lines

13. LT: I can graph and write equations of lines
Vertical Lines
Slope is undefined.
Equation form is x = #.
Write an equation of a line and graph it with undefined slope and passes through (1, 0).
x = 1
Write an equation of a line that passes through (3, 5) and (3, -2).
x = 3
LT: I can graph and write equations of lines

14. LT: I can graph and write equations of lines
Graphing Lines
*You need at least 2 points to
graph a line.
Using x and y intercepts:
(plug 0 in for x and then y)
Find the x and y intercepts
Plot the points
Draw your line
LT: I can graph and write equations of lines

15. Graph using x and y intercepts 2x – 3y = -12
x-intercept
2x = -12
x = -6
(-6, 0)
y-intercept
-3y = -12
y = 4
(0, 4)
LT: I can graph and write equations of lines

16. Graph using x and y intercepts 6x + 9y = 18
x-intercept
6x = 18
x = 3
(3, 0)
y-intercept
9y = 18
y = 2
(0, 2)
LT: I can graph and write equations of lines

17. LT: I can graph and write equations of lines
Graphing Lines
Using slope-intercept form y = mx + b:
Change the equation to y = mx + b.
Plot the y-intercept.
Use the numerator of the slope to count the
corresponding number of spaces up/down.
Use the denominator of the slope to count the corresponding number of spaces left/right.
Draw your line.
LT: I can graph and write equations of lines

18. Graph using slope-intercept form y = -4x + 1:
y-intercept
(0, 1)
Slope
m = -4 = -4 1
LT: I can graph and write equations of lines

19. Graph using slope-intercept form 3x - 4y = 8
y = 3x - 2 4
y-intercept
(0, -2)
Slope
m = 3 4
LT: I can graph and write equations of lines

20. LT: I can graph and write equations of lines
Homework
Homework: p. 78 #7, 11, 19, 23, 25, 27, 29, 33, 37, 39, 43, 49, 53, 58 Challenge - # 62
LT: I can graph and write equations of lines