2.1.7 Pre-Algebra (homework.cpm.org-select the Course 3 textbook)
• 2-67. Sylvia simplified the expressions on the expression
comparison mat shown at right. Some of her work is shown.
Are all of her moves "legal""? Explain.
Preview
(Associative or Commutative
Property) was used for each step
and write it in the table.
2-68. Examine the work at right that shows one way to simplify the expression 3x + 8 + (x+10).
Decide which property
Expression
What property was used?
. 2-69. Examine the tile pattern at right.
a. Draw Figures 4 and 5.
3x+8+(x+10)
(3x+8+x)+10
(3x+x+8)+10
(4x+8)+10
4x+(8+10)
4x+18
Original expression
a.
b.
Added like terms
C.
Added like terms
Figure 1 Figure 2 Figure 3
Which
gmater?
b. What would Figure 10 look like? How many tiles would it have? What about Figure 100?
Figure Number
Number of Tiles
3 4
17
1 2
9 13
S
c. Cami has a different tile pattern. She
decided to represent the number of tiles
of her pattern in a table (at right). Can
you use the table to predict how many
tiles would be in Figure 5 of her tile pattern? How many tiles would Figure 8 have? Explaim
how you know.