Cambridge International Mathematics

680 ANSWERS

EXERCISE 3B

1ax=¡^14 bx=¡ 18 c x=¡ 5 dx=18

ex=¡ 1 fx=¡^15 gx=¡ 1 hx=¡ 5

i no solution

2ax=15 bx=4^12 c x=17^12 dx=2^14

ex=^38 fx=¡ 127 gx= 154 hx=¡ 152

3ax=1 bx=¡ 1 c x=8^12 dx=¡ 12

ex=^15 fx=¡ 1

4ax=12 bx=¡^365 c x=¡^165 dx=^137

ex=16 fx=^407 gx=^163 hx=^115

i x=^5528 j x=^45 kx=¡^65 l x=^1724

EXERCISE 3C

1ax+6=13 b x¡5=¡ 4 c 2 x+7=1

d

x¡ 1

2

=45 e 3 x=17¡x f 5 x=x+2

2ax+(x+1)=33 bx+(x+1)+(x+ 2) = 102

c x+(x+2)=52 dx+(x+2)+(x+4)=69

3a 40 t+ 25(10¡t) = 280 b 40 p+ 70(p¡3) = 340

c 250 t+ 720t= 2910

EXERCISE 3D

1 7 237 and 38 3 19 413 550

6 84 75 roses 8 17 five cent and 23 ten cent

9 16 of 6 -pack, 9 of 10 -pack

EXERCISE 3E

1ax¼§ 3 : 32 bno solutions exist c x¼§ 8 : 43

dx¼ 9 : 43 ex=2 f x¼ 2 : 22 gx¼¡ 2 : 22

hx=§ 3 i no solutions exist j x¼ 1 : 87

kx¼¡ 2 : 57 l x¼ 1 : 84

2ax=§

p

12 (or § 2

p

3 ) b x=§ 6 c x=§

p

3

dx=§ 7 ex=§

p

10 f x=§

p

35

gx=§ 4 hno solutions exist

EXERCISE 3F

1a b

cd

ef

gh

ij

kl

2ax> 0 b x 6 ¡ 2 c x> 100

dx< 0 : 2 e ¡ 16 x 64 f 36 x< 10

g¡ 5 <x< 5 h 7 <x 620

i x< 2 orx> 7 j x<¡ 3 orx> 0

kx 64 orx> 17 l x 621 orx> 33

EXERCISE 3G

1ax 63 b x>¡ 6 c x 67

d x<¡^23 e x>^95 f x (^613)
gx>¡ 3 h x< 1 i x 6 ¡^15
2ax 64 b x>¡ 5 c x>¡ 4
d x>^73 e x< 1 f x (^635)
3ax>¡^72 b x>^43 c x (^613)
d x> 1 e x< 0 f x 6 ¡^53
4aNo solutions as 16. bTrue for all realx, i.e.,x 2 R.
c True for all realx, i.e., x 2 R.
d No solutions ina, an infinite number of solutions forb, and
an infinite number of solutions incwhen 2 x¡4=2(x¡2).

Review set 8B

1ax=¡ 10 b x=19 2ax=2^67 bx=¡ 2

3ax= 151 bx=9 4ax=7 bx=¡^17

5a b

6ax< 3 b x>¡ 7

7a2(x+ 11) = 48 bx+(x+1)+(x+2)=63

8 The number is 7. 9 twelve 5 -cent coins

10 a x=§ 2 bx=§

p

21

Review set 9A

1ax=8 bx=9 2ax=^34 bx=1

3ax=¡ 423 b x=4^14 4ax=1^19 bx=¡ 2

5a b

6ax 69 b x>^14

7a 4 x=x+15 bx+(x+2)=36 8 The number is 7.

9ax=4 bno solutions exist 10 332 votes

EXERCISE 4A

1ay=44 bx= 122 c x= 141 dy= 180

e y=99 fx=y=90

2ay=55fangles in right angleg

b f= 117 fco-interior anglesg

c c= 102 fco-interior anglesg

d y=65falternate anglesg

3 x -6 x 7 x

5 x 1 x

2 x -1 x

-2 2 x -3 4 x

1 6 x -1 0 x

0 3 x -1 2 x

2 5 x -2 0 x

-\_We x Ot_ x Qe_ x

-3 x 1 x -\Qt_ x

4 x -5 x -4 x

Ue_ x 1 x Et_ x

-\_Uw x Re_ x -\Qe_ x

1 x 0 x -\Te_ x

0 3 x

3 x -7 x

-1 3 x

-2 2 x -5 -1 x

9 x Qr_ x

IB MYP_3 ANS

cyan magenta yellow black

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100 100
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Y:\HAESE\IGCSE01\IG01_an\680IB_IGC1_an.CDR Thursday, 20 November 2008 4:07:03 PM PETER