Cambridge International Mathematics

7 Findkandngiven that k£ 2 n= 144 and k£ 8 n=9:

8 Solve forx, correct to 2 decimal places:

a 5 x=90 b 3 ¡^2 x=0: 05 c 20 £ 20 :^2 x=50

9 The number of employees in a company aftertyears is given by N=30£ 2

t 4

.

a How many people were employed originally?

b Find the number of employees after: i 4 years ii 7 years.

c GraphNagainstt.

d How long will it take for the company to grow to 200 employees?

Review set 28B

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1 Use your calculator to evaluate, correct to 3 decimal places:

a^3

p

25 b^5

p

100 c^4

p

15 : 1

2 Evaluate without using a calculator:

a 81 ¡

(^14)
b 4
(^52)
c 64
(^23)
d 81 ¡
(^54)
3 If P(x)=2£ 3 ¡x, find the value of:
a P(0) b P(1) c P(2) d P(¡1) e P(¡2)
4 On the same set of axes, without using technology, draw the graphs of y=2x and y=3£ 2 x:
a State they-intercepts and the equations of the horizontal asymptotes.
b What transformation is needed to draw the graph of y=3£ 2 x from the graph of y=2x?
5 Suppose f(x)=2x.
a Express in the form k£ax:
i f(¡x) ii f(2x) iii f(x+1) iv f(x¡1)
b Sketch all five graphs on the same set of axes.
6 Solve forx:
a 5 x+1= 251 b 272 x=^13 c 8 x=4^5 ¡x
d 14 £ 93 ¡^2 x=14 e 3 £
¡ 1
4
¢x+1
=96 f 7 x
(^2) ¡x
=49
7 Suppose 3 x¡^2 y=27and 22 x+y= 161. Findxandy.
8 Solve forx, correct to 2 decimal places:
a 3 x=20 b 72 x=¡ 1 c 12 £ 5 ¡^0 :^01 x=10
9 At the zoo, Terry the giant turtle is overweight. It is
decided to put him on a diet. His weighttweeks after
starting the diet is given byW= 130£ 3 ¡^0 :^01 tkilograms.
a How much did Terry weigh before he was started on
the diet?
b How much weight will Terry have lost after:
i 2 weeks ii 6 weeks?
c The keepers would like Terry to lose 20 kg. How long will it take to achieve this?
578 Exponential functions and equations (Chapter 28)
IGCSE01
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Y:\HAESE\IGCSE01\IG01_28\578IGCSE01_28.CDR Monday, 27 October 2008 2:44:13 PM PETER