Determine slope and intercept from an equation

8 teachers like this lesson

Print Lesson

Objective

SWBAT determine the slope and y-intercept from any linear equation.

Big Idea

Y has been a very, very bad boy. :) Isolate him so that we can figure out the slope and intercept.

Lesson Author

Jeff Li MTP

New York, NY

Grade Level

Eighth grade

Subjects

Math

Algebra

Function Operations and Inverses

Standards

8.F.A.3

Interpret the equation y = mx + b as defining a linear function, whose graph is a straight line; give examples of functions that are not linear. For example, the function A = s<sup>2</sup> giving the area of a square as a function of its side length is not linear because its graph contains the points (1,1), (2,4) and (3,9), which are not on a straight line.

MP2

Reason abstractly and quantitatively.

MP6

Attend to precision.

MP7

Look for and make use of structure.

Warm-up

10 minutes

Each day, students complete a Warmup that usually consists of spiraling the previous day's material, in addition to older material. Warm-up problems also sometimes extend lessons that students have encountered before to more unfamiliar contexts.

For a video narrative about how I structure each lesson, and how the warm-up fits in, click here.

I really like the warm-up problems today, because they push kids to apply their understanding to unfamiliar problems - in this case, focusing on matching the equivalent graphs and equations... I like to ask: "Which answer choice is wrong, and why?" Kids then use reasoning about the positive or negative nature of the slope, as well as where the line crosses the y-axis, which enriches their understanding of multiple representations of linear functions.