Algebra 1 Chapter 8 Closure

CL 8-112.Factor and use the Zero Product Property to find the roots of the following quadratic equations.

  1. 0 = x2− 7x + 12
  2. 0 = 6x2− 23x+ 20
  3. 0 =x2− 9
  4. 0 =x2+ 12x+ 36

CL 8-113.The price of milk has been steadily increasing 5% per year. If the cost of a gallon is now $3.89:

  1. What will it cost in 10 years?
  2. What did it cost 5 years ago?

CL 8-114. Use the graph at right to answer the questions below.

  1. One of these lines represents Feng, and one represents Wei. Write an equation for each girl’s line.
  2. The two girls are riding bikes. How fast does each girl ride?
  3. When do Feng and Wei meet? At that point, how far are they from school?

CL 8-115.Graph y =x2− 2x. Identify the y-intercept, x-intercepts, and the vertex.

CL 8-116.Find the coordinates of the y-intercept and x-intercepts ofy=x2− 2x− 15. Show all of the work that you used to find these points.

CL 8-117.Without using a calculator, simplify using only positive exponents.

CL 8-118.Quinn started off with twice as much candy as Denali, but then he ate 4pieces. When Quinn and Denali put their candy together, they now have a total of 50pieces. How many pieces of candy did Denali start with?

CL 8-119.Given the two points (−24, 7) and (30, 25),

  1. What is an equation of the line passing through the points?
  2. Is (51, 33) also on the same line? Explain your reasoning?

CL 8-120. Write the equation of the following two sequences in “first term” form.

  1. 100, 10, 1, 0.1, …
  2. 0, –50, –100, …

CL 8-121.Write the first four terms of the following sequences.

  1. an = 3 · 5n−1,...
  2. a1 = 10, an+1 = − 5an

CL 8-122. Bianca plays lacrosse for her high school team. She loves to look at the ratings of lacrosse teams that play in her area. She wondered if she could predict the differences in the final scores when two teams played each other. Bianca looked at the differences in ratings and scores between different pairs of teams and drew the following scatterplot by hand.

  1. Discuss the association, including an interpretation of slope and R-squared.
  2. Predict the outcome of a game between Novato (rating 74.27) and Marin Catholic (rating 76.61).
  3. The difference in rating between Woodbridge and Lakeside was 5.00. When they played, their residual was 7. What was the difference in their scores in this game?

Problem / Solutions / Need Help?
CL 8-112. / a. x = 4 or x = 3
b.x =or x =
c.x = −3 or x = 3
d.x = −6 / Section 8.2
MN: 8.2.2
LL: 8.2.2
CL 8-113. / a. $6.34
b. $3.05 / Section 5.3
LL: 5.1.1 and 5.3.2
CL 8-114. / a. Feng: y = 4x Wei: y = 6x − 12
b.Feng rides at 4 miles per hour;
Wei rides at 6 miles per hour.
c.Feng and Wei meet after 6hours. At that point, they are 24 miles from school. / Chapter 2
MN: 2.2.2
LL: 2.2.2
CL 8-115. / y-intercept: (0, 0)
x-intercepts: (0, 0) and (2, 0)
vertex: (1, −1) / Lesson 1.1.3
Section 8.2
CL 8-116. / y-intercept: −15
x-intercepts: 5 and −3 / Section 8.2
LL: 8.2.3
CL 8-117. / a. 9x2
b.
c.
d. −4x5 / Lesson 7.2.1
MN: 7.2.2
LL: 7.2.1
CL 8-118. / Denali has 18 pieces of candy. / Chapter 4
Checkpoint 7A
Checkpoint 7B
MN: 4.2.3
CL 8-119. / a.y =x + 15
b. No, it does not work in the equation. / Lessons 2.1.4 and 2.3.1
Checkpoint 5B
LL: 2.3.1
CL 8-120. / a. t(n) = 100 · 0.1n−1
b. t(n) = 0 − 50(n − 1) = −50(n − 1) / Section 5.2 and 5.3
CL 8-121 / a. 3, 15, 75, 375
b. 10, −50, 250, −1250 / Section 5.2 and 5.3
CL 8-122 / a. There is a very strong positive linear association between the differences in ratings and the corresponding difference of game scores. There are no apparent outliers. About 81% of the variation in score differences is explained by the difference in ratings of the two teams. The slope is about 1.6. An increase of 1 in the difference of ratings is expected to increase the score difference by 1.6 points.
b.The LSRL is about y = 1.6x. y = 1.6(74.27 −76.61) = −3.74. Marin Catholic is expected to win by about 4 points.
c.The model predicts the difference in scores to be y = 1.6(5) = 8points. Since residual = actual −predicted, 7=actual= −8. The actual difference in scores was 15points. / Chapter 6
Checkpoint 8

Answers and Support for Closure Activity #4:
What Have I Learned?

Note: MN=Math Note, LL=Learning Log