Noelani Davis EASTERN Senior High School, WASHINGTON, DC
Algebra I : Unit #5 - Graphing Linear Functions : Lesson #4

Graphing Linear Functions in Standard Form (Day 2 of 2)

Objective: SWBAT graph linear functions in standard form by solving the equation of the line for its y-coordinate.
Standards: 8.F.A.1 HSA-SSE.A.1 HSS-ID.C.7 MP4 MP7 MP8
Subject(s): Math
60 minutes
1 Do-Now - 10 minutes

Students will complete the Do Now in 5 minutes. 

When students lost points on previous assignments because of sign and integer errors they often gripe, "But - I just missed the sign!!! But - I was only off by one number!!!"

The aim of this Do-Now is for students to understand how something as minuscule as the presence of a negative sign can change the entire outcome of an equation. The Do-Now and today's lesson both allow students to practice MP6, as students will be solving equations and must pay special attention to accuracy.

We will review the answers to the Do-Now aloud. I will ask students to score their own paper, and to keep their Do-Now out on their desk as a guide if they feel like they are still struggling with this skill.

Next, a student will read the objective: "SWBAT graph linear functions in standard form by solving the equation of the line for its y-coordinate". 

I will ask students to recall how we have graphed lines throughout the school year (slope intercept form). I will then ask students to compare the appearance of standard form vs. slope intercept form.

2 Guided Notes + Practice - 20 minutes

Before beginning today's lesson, the class will review graphing lines in standard form with intercepts using the Standard Form Two presentation. I will call on a student volunteer to come to the front of the room to review the exit card from our last class on the board.  

Slide 4: Students will initially complete Example One on their notes by solving for the x and y intercept:

x intercept: (5.25, 0)

y intercept:(0, 3.5)

I will then ask students to think about what challenges may arise when we attempt to analyze the points on the graph. Since we're graphing decimals, the points that we plot are in estimated locations. Can we find a more accurate solution?

I will ask the class to recall the definition of a literal equation. Once students see that the equation of a line (whether in standard OR slope intercept form) is a literal equation, we realize that we can manipulate the equation to suit our needs by solving for y - thus putting the line in slope intercept form.

"MX + B" vs "B + MX"
Adjustments to Practice

This lesson had high levels of student mastery, students could do this fluently. A key takeaway I shared with students was when we solve for y, isolate the variable. When solving the equation, write the “mx”  term first, then the constant term. All year, even with literal equations and systems of equations later on in the year, students would always put the “mx” pair together.

3 Partner Activity - 40 minutes
The goal of this activity is for students to practice converting lines that are in standard form to lines in slope-intercept form. Students will work in pairs to unscramble the cards to show the correct order of algebraic steps.

When students finish, the cards should be glued down on a piece of colored paper. 

Please enjoy this video which shows a student demonstrating this activity.


Instructional Note: The Standard Form Scramble Activity must be cut out and paper clipped by the teacher before class begins.

4 Closing - 10 minutes

Two volunteers will give a short summary about what we learned in class today. I will then ask students to share some of the advantages and disadvantages of the two different methods we have used to graph lines in standard form (using intercepts vs solving for y). Students will then complete an Exit Card. The exit cards should be graded directly after class, and the students should then be grouped by the percentage of correct questions for our next class.