Cambridge International Mathematics

720 ANSWERS

EXERCISE 21I

1ax¼¡ 3 : 414 or¡ 0 : 586 bx¼ 0 : 317 or¡ 6 : 317

c x¼ 2 : 766 or¡ 1 : 266 dx¼ 3 : 409 or¡ 1 : 076

ex¼ 3 : 642 or¡ 0 : 892 f x¼ 1 : 339 or¡ 2 : 539

2ax¼ 1 : 115 or¡ 0 : 448 bx¼ 1 : 164 or¡ 2 : 578

c x¼ 0 : 451 or 1 : 282

EXERCISE 21J

1 ¡ 11 or 10 26 or¡ 2 39 and¡ 3 4 1 5 11 metres

6 2 m 7 1212 mby 10 m 8

5+

p

5

2

and

5 ¡

p

5

2

9ax=

p

31 ¡ 1 b x=3+

p

5

2

10 BC=5cm or 16 cm 11 10 cm, 24 cm, 26 cm

12 ¼ 51 : 6 m 14 at=20 b 6 hours c 30 km/h

15 16 or ¡¡^105164 m 17 43 or^32

18 a i 75 m ii 195 m iii 275 m

bi 2 sec and 14 sec ii 0 sec and 16 sec

c Each height occurs once on the way up and once on the way

down.

19 a ia$40loss ii $480 b 10 or 62 cakes

20 Max takes 412 h, Sam takes 6 h 21 2 cm by 2 cm

22 b¼ 8 : 8 cm 23 8 cm, 15 cm, 17 cm

REVIEW SET 21A

1ax=§

p

2 b no real solutions c x=0or 3

dx=3or 8 e x=¡^25 or^32 f x=¡^73 or 3

2ax=0or 1 b no real solutions c x=2§

p

5

dno real solutions e x=1or¡ 313 f x=5or¡ (^112)
3ax=¡^1 §
p
3
2
bx=^2 §
p
2
2
4ax¼ 0 : 349 or¡ 1 : 635 bx¼§ 2 : 12
c x¼ 1 : 45 or¡ 3 : 45
5a¡ 15 b¡ 17 c x=6or¡ 3
6a b
c
7a iopens downwards
ii 6
iii 1 and¡ 3
iv x=¡ 1
b
8a i¡ 15
ii 5 and¡ 3
iii x=1
iv (1,¡16)
b
9 f(x)=x^2 +6x¡ 2
10 a V(2,¡1)
b 11
c
11 f(x)=2(x+1)^2 ¡ 5 12 f(x)=9x^2 +39x+12
13 f(x)=^92 x^2 ¡ 54 x+ 160 14 3
p
3 cm by
p
3 cm
15
15 + 30
p
2
7
cm 16 a x=2 b x=5 c x=6
17 a 2 seconds b 80 m c 6 seconds
REVIEW SET 21B
1ax=3 bx=¡ 5 or 4 c no real solutions
d x=8or¡ 3 ex=§ 2 f x=¡^12 or^23
2ax=2§
p
14 bx=
¡ 1 §
p
37
2
3ax=¡ 5 or 3 b x=2^12 or 4 c x=¡^13 or 3
4a 1 b 13 c x=¡ 2 or^32
5a
x b
y
@\=!X
@\=-(!+3)X-2
(-3' -2)
-11
O
x
y @\=!X
@\=(!-2)X+1
(2' 1)
5
O
x
y
@\=!X
@\=\3!X
O
x
y
@\=-2(!-1)(!+3)
!\=-1
(-1' 8)
6
-3 1
O
x
y
@\=!X-2!-15
-3
!\=\1
-15 (1' -16)
O 5
x
y
@\=!X
@\=-Qw_!X
O
x
y
@\=(!+2)X+5 @\=!X
(-2' 5)
O
y
V,()2 -1 x
11
O
yx¡=¡3 ¡-¡2 ¡-¡1()X
IB MYP_3 ANS
cyan magenta yellow black
(^05255075950525507595)
100 100
(^05255075950525507595)
100 100
Y:\HAESE\IGCSE01\IG01_an\720IB_IGC1_an.CDR Thursday, 20 November 2008 4:47:05 PM PETER