Ch 4 Equations of Linear Functions TEST Review

Writing Equations in Slope-Intercept Form

100

What is the equation for Slope Intercept Form 

y = mx + b

200

What do the variables m and b represent?

Slope and y-intercept 

300

How do you find slope when the line passes through the given two points?

m = y₂-y₁ / x₂-x1

400

Write equation in slope intercept form for the line that passes through the given point and has the given slope.  (2,-6) and slope is -4

y = -4x+2

500

Write equation in slope intercept form for the line that passes through the given points.  (3, 5) and(5, 6)

y = 1/2x + 7/2

Writing Equations in Standard and Point-Slope Form

100

What is the equation for Point-Slope Form?

y - y₁ = m(x - x₁)

200

What do the variable m, x₁, and y₁ represent?

slope, x and y value of given point

300

Write an equation in point-slope form for the line that passes through the given point with the slope provided.  (-2, 1), slope is -3

y - 1 = -3(x + 2) 

400

Given the point-slope form equation, write the equation in Standard Form. y - 9 = -4/5(x + 2)

4x + 5y = 37

500

Given the equation in point-slope form, write the equation in Slope-Intercept Form. y - 4 = 1/2(x + 2)

y = 1/2x + 5

Parallel and Perpendicular Lines

100

How would students describe what parallel lines and perpendicular lines look like on a coordinate plane?

Parallel - lines that never intersect and Perpendicular - lines that intersect creating 90^o (T shape)

200

In the equation y = mx + b, parallel lines have what in common?

Equal/Same slope (m) 

300

In the equation y = mx + b, perpendicular lines have what kind of difference?

m₂ is the opposite reciprocal, negative reciprocal, or the product of the two slopes equal to -1. 

400

Write an equation of a line in slope-intercept form for the line that passes through the given point and is parallel to the graph of each equation. (-5, -2), y = -1/2x + 4

y = -1/2x - 9/2

500

Write an equation of a line in slope-intercept form for the line that passes through the given point and is perpendicular to the graph of each equation. (1, 3), y = -2x - 4

y = 1/2x + 5/2

Scatter Plots and Lines of Fit

100

How do you describe a positive correlation? 

As x increases, y increases 

200

How do you describe a negative correlation?

As x increases, y decreases

300

How do you describe no correlation? 

x and y are not related (points every where on a graph)

400

What do students call the line in which you manipulate after creating a scatter plot?

Line of fit or best fitting line

500

BUSINESS: A scatter plot of data compares the number of years since a business has opened and its annual number of sales. It contains the ordered pairs (2, 650) and (5, 1280). By HAND: Write an equation in slope-intercept form for the line of fit for this situation.

y = 210x + 230

Linear Regression

100

Can students use a graphing calculator to find linear regression?

Yes

200

What are the steps when finding linear regression in the graphing calculator.

1. Enter the data by pressing STAT and selecting the Edit option. 

2. Enter the data into List 1 (L1). These will represent the x-values. Enter the data into List 2 (L2). These will represent the y-values.

3. Perform the regression by pressing STAT and selecting the CALC option. Scroll down to LinReg (ax + b) and press ENTER 5 times. 

4. Write the equation of the regression line by rounding the a and b values on the screen. The form we chose for the regression was ax + b, which is the same as y = mx + b

300

Turn to page 279 in the book and answer #43

y = 5.36x + 11; 65

400

Turn to page 279 in the book and answer #44

y = -5.79x + 199.14; $112.29

500

Turn to page 265 in the book and answer #13A

y = 84,345.0x + 5,003,868.3