Download Lesson 1 - SIF and Standard - Slope and Point with Parallel

Algebra 1
Name: _______________________________
Unit 3: L1
Date: _________________ Period: _______
Writing Equations of Lines in SIF and Standard Form (5.1, 5.2 , 5.6)
Essential Question:

What information is needed to determine the equation of a line?
Goal:
1) I can use slope-intercept form to write an equation of a line.
2) I can write a linear equation in standard form.
Vocabulary:
 Slope-Intercept Form: when equations in two variables (x, y) are solved for y, we can immediately
identify the slope and the y-intercept of the graph.
 Formula: y  mx  b
 Slope: the _____________ of the x term (m) and should stay as a fraction (no mixed numbers)
 Y-Intercept: the ______________ term and where the line crosses the y-axis (b)
2) Standard Form:
 Formula:
Ax + By = C
 The coefficient of x cannot be ________________
i. To undo this multiply everything on both sides by (-1)
 No ________________ or decimals can be present. A, B, and C all must be whole numbers.
i. To clear fractions ___________________ everything on both sides by the least
common denominator.
3) Parallel Lines:
 Two lines that never intersect
 NEW… Two lines are parallel if they have the ____________________ slope.
Steps for Slope-Intercept Form:
1) S lope - Find m
2) I ntercept - Find b
3) F orm - Put in y=mx+b form.
Steps for Standard Form:
1) Write in Slope-Intercept Form (SIF) First
2) Convert to Standard Form
Section 1: GIVEN SLOPE AND Y-INTERCEPT… Write the equation of the line in SIF and Standard Form.
PROBLEM
1) slope = -5
y-intercept = -2
S
I
F
Standard
PROBLEM
2) slope = 
S
I
F
Standard
3
2
y-intercept = 0.25
3) m = 0
b= 4
4) m =
1
5
b=0
Section 2: GIVEN SLOPE AND A POINT… Write the equation of the line in SIF and Standard form.
PROBLEM
5) slope = -2
passes through
(6 , -3)
S
I
F
Standard
F
Standard
6) m = undefined
passes through
(2 , -2)
7) m =
1
2
passes through
(5 , 6)
8) m = 0
passes through
(-7 , 1)
Section 3: PARRALEL… Write the equation of the line in SIF and Standard Form
PROBLEM
9) parallel to
y
2
x2
3
passes through
(-2 , 1)
S
I
// to
1
y  x2
4
10)
passes through
(-3 , 2)
11) // to y  5
passes through
(8 , 4)
Section 4: Keystone Applications
12) A plumber charges $66 for the first hour of a service
call and $45 for any additional hours.
YT 12) A rental company charges a flat fee of $30 and
an additional $0.25 per mile to rent a moving van.
A. Write a linear model of this situation in slopeintercept form.
A. Write an equation to model the total charge in
slope-intercept form.
B. Rewrite your equation from (A) into standard
form.
B. Rewrite your equation from (A) into standard
form.
C. Determine the cost of a 3-hour call.
C. Determine the price of the rental if you drove 102
miles
Homework:
pg 276 # 3 – 8 all
&
pg 282 # 3-10all
&
pg 311 # 7-9 all
Lesson summary / Ticket Out:
A) Describe the procedure for writing an equation of a line in slope-intercept form. What are the 3 steps? Is
there a helpful way to remember these steps?
B) What are the rules for standard form?
C) What is significant about the slopes of two parallel lines?