Page 36 - 新思维数学学生用书9 样章

2.3 Expressions and indices

8 Marcus and Arun simplify the expression (3x ) . Read what they say.
2 3

I think the I think the
6
answer is 3x . answer is 27x .
6

a Who is correct, Marcus or Arun? Explain why.

b Simplify these expressions.
i (4x ) ii (5y ) iii (2z )
4 3
7 4
5 2
Activity 2.3

a Make a copy of this spider diagram.
b In each empty circle, write an expression that
simplifies to the expression in the centre circle.

Use expressions similar to those in questions
4, 6 and 8.
c Swap your spider diagram with a partner’s 36x 12
diagram and mark each other’s work.
Discuss any mistakes that have been made.

9 Simplify these expressions.
Write your answers using a negative power and a fraction. Tip
Part a has been done for you.
Remember the rules
a q ÷ q = q 47 = q − 3 = q 1 3 b r ÷ r 5 for negative indices:
−
4
7
3
c t ÷ t 12 d v ÷ v 7 2 = 1 , 2 = 1 , 2 = 1 ,
6
7
−
−
−
3
1
2
3
10 Here are six rectangular cards and seven oval cards. etc. 2 1 2 2 2
The expressions on the rectangular cards have been
simplified to give the expressions on the oval cards.
A 5y ÷ 10y 8 B 3y ÷ 9y 7 C 4y ÷ 6y 8
2
6
4
D 9y 4 E 15y 2 F 15y
12y 7 10y 6 12y 3

35