1. Written Practice
Lesson 20

2. 1.
(+3) + (-14)

3. 2.
4xyz – 3yz - zxy

4. 3.
3xyz – 3xyz + xyz

5. 4.
x – 4 = 10

6. 5.

7. 6.
Graph the ordered pair (3,-4) on a coordinate plane.

8. 7.
Graph the ordered pair (0, 5) on a coordinate plane.

9. 8. Which ordered pair is associated with point Z?
(3,0) B. (0,3)
C. (-3,0) D. (0,-3) y x Z

10. 9. Ellen charges $3 plus $1 per child for an hour of babysitting
9. Ellen charges $3 plus $1 per child for an hour of babysitting. To determine her hourly rate, she uses the formula r = 3 + c, where r is the rate and c is the number of children. Complete the table and graph the solutions.
r = 3 + c c r 1 2 3 4

11. 10. Thomas read 10 pages in a book before starting his speed-reading lessons. After his lessons, he could read 3 pages per minute. The equation y = 3x + 10 calculates the total number of pages read after x minutes. Complete the table. x y 15 20 30 50

12. Two students completed an x/y chart for the equation y = 3 + 2x to find a solution to the equation. Which student is correct? Explain.
Student A Student B x y 2 7 x y 2 10
y = 3 + 2(2)
y = 5(2)
y = 10
(2,10) is a solution
y = 3 + 2(2)
y = 3 + 4
y = 7
(2,7) is a solution

13. Complete the table and graph the solutions.
For a lemonade stand, profit depends on the number of cups sold. Profit is represented by the equation y = x – 5, where x is the number of cups sold and y is the profit in dollars. x 5 10 20 50 y
y = x - 5
Complete the table and graph the solutions.
b. How would you find the profit if 30 cups were sold?

14. The triangle has a perimeter of 24 centimeters. Find the value of x.
13.
The triangle has a perimeter of 24 centimeters. Find the value of x.
8 cm
10 cm

15. 14. To climb to the highest observation deck in the Empire State Building, you have to walk up 1860 steps. Starting at the lowest step, a security guard walks up ¼ the total number of steps during his morning rounds. At the end of his afternoon rounds, he stands on the 310th step. How many steps did he walk down during the afternoon rounds?

16. Two students simplify the expression 5x2 + 7 x2
Two students simplify the expression 5x2 + 7 x2. Which student is correct? Explain.
Student A Student B
12x2
12x4

17. 16.
Why do mathematicians use symbols rather than words?
They use symbols because….

18. 17. Which equation demonstrates the Associative Property of Addition?
6 – 3c = 3c B. c3 – 6 = c3 +6
C. (6 – c)3 = (c – 6)3 D. (6 + c3) – 4 = 6 + (c3 – 4)

19. 18. Evaluate each of the following expressions when a = 2.
A. a2 B. -a2 C. -a3 D. (-a)3 E. |(-a)2|

20. 19. A school is holding a blood drive
19. A school is holding a blood drive. If 3 students out of the 50 who give blood are Type A, what is the probability that a randomly selected student is Type A? Write the probability as a decimal.

21. 20. Evaluate

22. 21.
Use an example to show that the Associative Property holds true for multiplication.

23. Decrease in Number of Deer
22. Use the data in the table to find the average yearly change in the deer population during a five year period.
Deer Population
Year
Decrease in Number of Deer
2000 10
2001 7
2002 9
2003
2004 12

24. 23.
A Stock Market Report shows the value of stocks in points. The value of the stock is determined by the number of points. If a stock is at 79 5/7 points and it drops 3 points, what is the value of stock?

25. 24.
One hundred grams of honey contains about 0.3 grams of protein. How many milligrams is 0.3 grams?

26. 25.
A contractor lays patterned tile floors. He often begins with a polygon and makes a diagonal lines that pass from corner to corner of the polygon. He uses the following expression , where n equals the number of sides of the polygon to find the number of diagonal lines for any given polygon.
Find the number of diagonals for a hexagon.
Check your work by drawing the diagonals in a hexagon.

27. 26.
Write and simplify a mathematical expression that shows “fourteen minus the quotient of three squared and the sum of three plus six.”

28. 27.
Indicate whether each statement is true or false. If the statement is false, explain why.
a. The coefficient of x in the expression
x + 3 is 3.
The factors of the expression are
, m and n.

29. 28.
Name the coefficient(s), variables, and number of terms in the expression b2 – 4ac.

30. 29.
Pencils cost ten cents and erasers cost five cents.
Write an expression to represent the total number of school supplies purchased.
b. Write an expression to represent how much the supplies cost in cents.

31. 30.
A person runs 5 miles per hour. The equation d=5t tells how far the person has run in t hours. Make a table when t = 0, 1, 2, and 4 hours. Graph the ordered pairs in a graph and connect all the points.
What do you notice?