Chapter 5 Review

5.1 Write Linear Eqns in Slope-Intercept Form Example 1 Write an equation of the line shown.

Step 1: y = mx + b Step 2: Find b. (y-intercept) b = 4 Step 3: Find m. (slope = rise/run) m = -2/3 Step 4: Write equation y = (-2/3)x + 4

Assignment: Pg. 345 # 4 - 6

You have a $25 gift card for a bagel shop. A bagel costs $1. 25 You have a $25 gift card for a bagel shop. A bagel costs $1.25. Write an equation that gives the amount (in dollars) that remains on the card as a function of the total number of bagels you have purchased so far. How much money is on the card after you buy 2 bagels? T = 25 - 1.25b (b= number of bagels, T = total) T = 25 - 1.25(2) = $22.50

5.2 Use Linear Equations in Slope-Intercept Form Example 2 Write an equation of the line that passes through the point (-2,-6) and has a slope of 2. Step 1: y = mx + b Step 2: Find b (y-intercept) y = mx + b -6 = 2(-2) + b -6 = -4 + b +4 +4 -2 = b Step 3: Write Equation y = 2x - 2

Assignment: Pg. 346 # 8 - 10

5.4 Write Linear Equations in Standard Form Example 3 Write an equation in standard form of the line shown. (-1,1) and m = -2

(-1,1) and m = -2 Step 1: y = mx + b Step 2: Find b 1 = (-2)(-1) + b -2 -2 -1 = b Step 3: Write equation y = -2x - 1

Assignment: Pg. 347 # 15 - 16

5.5 Write Equations of Parallel and Perpendicular Lines Example 4 Write an equation of the line that passes through (-4,-2) and is perpendicular to the line y = 4x - 7. Hint: Perpendicular lines have slopes that are the negative reciprocal of each other. Step 1: Find slope. y = 4x -7 m = 4, so slope of perpendicular line is - 1/4.

Write an equation of the line that passes through (-4,-2) and is perpendicular to the line y = 4x - 7. Step 2: Find b. y = mx + b -2 = (-1/4)(-4) + b -2 = 1 + b -1 -1 -3 = b Step 3: Write Equation y = (-1/4)x - 3

5.5 Write Equations of Parallel and Perpendicular Lines Example 5 Write an equation of the line that passes through (-4,-2) and is parallel to the line y = 4x - 7. Hint: Parallel lines have the same slopes. Step 1: Find slope. y = 4x - 7 m = 4, so the slope of a parallel line is 4.

Write an equation of the line that passes through (-4,-2) and is parallel to the line y = 4x - 7. Step 2: Find b. y = mx + b -2 = 4(-4) + b -2 = -16 + b +16 +16 14 = b Step 3: Write equation. y = 4x + 14

Assignment: Pg. 347 # 18 - 20

5.6 Fit a Line of Data Example 6 The table shows the time needed to roast turkeys of different weights. Make a scatter plot of the data. Describe the correlation of the data. Weight (pounds) 6 8 12 14 18 20 24 Roast time (hours) 2.75 3.00 3.50 4.00 4.25 4.75 5.25

Make a scatter plot of the data. Describe the correlation of the data. Because the graph rises from left to right, it has a positive correlation

5.6 Fit a Line of Data Step 1: Find the pattern on the data. - positive correlation - rises from left to right. - negative correlation - falls from left to right. - no correlation - no real pattern. Step 2: Draw line. half the points above and half the points below. Step 3: Write equation. y = mx + b

Assignment: Pg. 348 # 21

5.7 Predict with Linear Models Example 7 Use the scatter plot from the example for Lesson 5.6 above to estimate the time (in hours) it takes to roast a 10 pound turkey. Step 1: Draw scatter plot Step 2: Draw Line of best fit. Step 3: Find x-coordinate and y-coordinate on the line.

It takes about 3.25 hours to cook a 10 pound turkey. Use the scatter plot from the example for Lesson 5.6 above to estimate the time (in hours) it takes to roast a 10 pound turkey. It takes about 3.25 hours to cook a 10 pound turkey.

Assignment: Pg. 348 # 22

Assignment Pg. 942 #2-8 even, 22 - 30 even