mtcorps wiki / Identifying slope from Equations

The students will find the slope of a line given a linear equation in slope-intercept form (Algebra I 7.a)
The students will find the slope of a line given a linear equation in standard form (Algebra I 7.a)

Materials:

Overhead, transparencies, dry erase board, dry erase markers, pencils, paper, calculators

Set:

Display quiz on transparency (10 minutes):

Quiz

1. Find the slope of a line having the following points: (3, 8) and (-2, 8) (Answer = 0)

2. Find the slope of a line from a graph.

3. Graph the line y = 2x – 3 using a table. (Use at least three values of x.)

4. Determine whether listed relations are functions:

a. Contains points (2, 3), (4, 3), (5, 7), (3, 6)

b. Contains points (2, 5), (2, 3), (5, 8)

c. Mapping diagram that is not a function

d. Mapping diagram that is a function

e. A graph that is not a function

f. A graph that is a function

5. If g(t) = 2t – 5, g(3) = (Answer = 1)

BONUS! Find the slope of a line having the following points: (2, 5) and (2, 3) (Answer = undefined)

Go over quiz and review previous day’s learning using track race graph as example. Remind students that positive slope means line rises from left to right; negative slope means line goes down from left to right. Slope pertains to the steepness of a line. The steeper the line, the greater the absolute value of the slope. Last lesson was an introduction to slope. Today’s lesson is about how to determine the slope of a line given two forms of the equation of a line: slope-intercept form and standard form. Slope-intercept form is y=mx+b, and standard form is ax+by = c.

Procedures:

I will show students that given an equation in slope-intercept form, m is the slope and b is the y-intercept. (Slope is coefficient of x, y-intercept is the constant.)

Students will identify slope and y-intercept in the following problems, and will tell whether line is sloped up or down:

Ex 1 y=4x – 5

Ex 2 y= -2x + 5

Ex 3 y = 3 + 2x

Ex 4 -3x + 4 = y

Ask students which line is the steepest.

I will show students standard form ax + by = c, and ask them to solve for y. (2 minutes)

Show students that it can be changed to slope-intercept form, and that slope is –A/B, and y-intercept is C/B.

Students will identify slope and y-intercept in the following problems:

Ex 5 3x-5y = 10

Ex 6 -10x – 2y = 100

Ex 7 6y – 3x = 18

Have students convert Ex 7 to slope-intercept form.

Have students write an equation in slope-intercept form with m = 5 and b = -3.

(Extra problems: p. 413 5-19)

Time permitting, I will allow students to play an 8 card memory game, in which they match an equation with the slope or y-intercept of the equation.

I will close prior to assigning homework.

Closure:

I will ask students to take out a sheet of paper to do an exit slip. I will put two equations on the board: y = -2/3x +3 and -3y + 2x = 9. I will ask students to determine the slope and y-intercept of each line. I will go over the problem. Today’s objectives were to determine the slope of a line from a linear equation written in slope-intercept form, and from a linear equation written in standard form. The next lesson will be on finding slope of a line from a graph and given two points.

Assessment/Evaluation:

Informal:

The students will be informally assessed on using finding the slope of a line from linear equations (C) while doing their warm-up, guided practice, and some of their homework. I will walk around the classroom, checking the students’ work (M), and will document in a notebook (D).

Formal:

The students will be assessed on their ability to find the slope of a line given an equation (C), once on their homework assigned this period (M) and once on the Friday, June 22 test (M). Both of these grades will be recorded in the grade book.

mtcorps

Identifying slope from Equations

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