Page 33 - 新思维数学学生用书9 样章

2 Expressions and formulae

Worked example 2.3

Simplify each expression.
4
a x × x b y ÷ y c ( ) d 6w + 2w 4
4
3
4
7
3
2
z
Answer
a x × x = x 2 + 3 To multiply, add the indices.
2
3
= x 5 2 + 3 = 5, so the answer is x .
5
b y ÷ y = y 7 – 4 To divide, subtract the indices.
7
4
= y 3 7 − 4 = 3, so the answer is y .
3
4
3
×
c ( ) = z 34 To simplify the power of a power, multiply the indices.
z
3 × 4 = 12, so the answer is z .
12
= z 12
6w and 2w are like terms, so add 6 and 2 together.
4
4
d 6w + 2w = 8w 4
4
4
The index stays the same.
Exercise 2.3
1 Copy and complete
a x × x = x 45 b y × y = y 24
+
+
5
2
4
4
= x = y
c u ÷ u = u 86 d w ÷ w = w 5 1
−
5
8
6
−
= u = w
12
2
e g ( ) = g 32 f h ( ) = h 512
×
5
×
3
= g = h
g 5m + 3m = m 3 h 8n − n = n 2
3
2
2
3
2 Simplify each expression.
a m × m 6 b n × n 3 c p × p d q ÷ q 4
8
6
9
9
e r ÷ r 3 f t ÷ t 2 g ( ) 3 h ( ) 5
7
2
x
7
6
y
i ( ) 4 j 3t + 2t 7 k 8g − 3g 2 l 3h + h − 5h 9
9
3
7
9
2
z
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