3 3-3

1.0 abc abc

2.xyzabc xyz=abc

3.xyz=abcxy=ab

yz=bcxz=ac (1)

(2)x=ary=brz=cr (r0)

345 (1)2 (2)240

(1)x 35=2x

3x=10

(2)xyz xyz=345x=3ry=4rz=5r x+y+z=240 3r+4r+5r=240 12r=240 r=20 6080100

4.xy=abyz=bcxyz=abc

xy=23yz=65xyz

1.ab=12bc=34cd=56 (1)ad (2)a+b+c+d=266b=

a=15rb=30rc=40rd=48r 15r+30r+40r+48r=266r=2ad = 1548 = 516b = 30r = 60(1)516 (2)60

2.ab=323c=5b(1)abc (2)a+b+c=75a=

3c = 5bbc = 35 a=9rb=6rc=10r9r+6r+10r=75r=3a=9r=27(1)96 10 (2)27

3.y(2x-y)(x-1)=133x+y=y=r2x-y=3rx-1=3ry=rx=3r+12(3r+1)-(r)=3r5r+2=3rr= -1x= -2y= -1x+y= -3-3

4.(x+1)(y-2)(z+3)=456x+2y+3z=90 x-y+z

x+1=4ry-2=5rz+3=6rx=4r-1y=5r+2z=6r-3(4r-1)+2(5r+2)+3(6r-3)=9032r-6=90r=3x=11y=17z=15x-y+z = 99

5.2x+y-z=0x-2y+z=0xyz0xyz=

(1)+(2) 3x-y=0y=3x(1) 2 +(2) 5x-z=0z=5xxyz = x 3x5x = 135 135

6.abc3a=6b=2c(1) abc=

(2) 3a=6b=2c=rabc = 213

7.xyz02xy=3yz=5zxxyz=

2xy=3yz=5zxxyz =352 352

8.10(y+z)=12(z+x)=15(x+y)(1)xyz (2)yzzxxy355

10(y+z)=12(z+x)=15(x+y)=60r (1)+(2)-(3) 2z=7r z=7r/2 y=5r/2 x=3r/2xyz = 3 57

xyz = 3 57yzzxxy = 35 2115 (1)357 (2)17510575

9.137500 543123 (1) (2)

= (5 1)(4 2)(3 3) = 589 (1)589 (2)312505000056250

10. 5205 20 (1) (2)18

VVV25V=20V25V=20VVV=45VV=45VV=1620VV=2025VVV=162025

x V=16rV=25r16r (x+18)=25r(x)16x+288=25x288=9xx=32 (1)162025 (2)32

1.xyz=234(x+2y+z)y= (A)31 (B)41 (C)51 (D)61

x=2ry=3rz=4r(x+2y+z)y= (2r+6r+4r) 3r = 12r3r = 41 B

2.xy=23xz=34x2yz (A) (B) (C) (D)

xyz 23 3 4 xyz 69 6 8 698x2yz=(6r)2(9r)(8r) = 36r272r2 = 12 B

3.ab= bc= abc= (A)945 (B)163645 (C)204536 (D)452016

a b c 9 4 5 4 45 2016 D

4.3xy=578x+y= (A)7 (B)8 (C)9 (D)10

3xy = 5785x=215y=24x+y= 9 C

5.x3y2z=121x+z=27 (A)x=15 (B)y=12 (C)z=6 (D)y+z=18

x=r3y=2r2z=ry=2r/3z=r/22r+r=54 r=18 x=18y=12z=9 B

6. (A)4x=x9x=6 (B)3a=4b=5cabc=345 (C)(x+y)(x-y)=31xy=(-1)1 (D)4x = x9x2=36x= 63a=4b=5cabc = (4)(5)(3)(5)(3)(4)= 201512(x+y)(x-y)=31x+y=3rx-y=r2x=4rx=2ry=r D

7. 2a+3b+4c=114bx=12c-16ax=

(A)4 (B)3 (C)2 (D)1

a=3rb=4rc=5r2(3r)+3(4r)+4(5r)=11438r=114r=3a=9b=12c=1512x=180-144bx=12c-16ax=3 B

8.ab=233b=5cac= (A)76 (B)109 (C)85 (D)910

3b=5cbc = 53 a b c 2 3 5 3 10 15 9 B

9.ab= bc= a2bc= (A)10912

(B)101824 (C)51812 (D)5912

a b c 5 9 3 4 5 9 12a2bc = 51812 C

10.abc02a=4b=3c (1) abc= (2)5a+4b+3c=162a-b+c=

2a=4b=3cabc=(4)(3)(2)(3) (2)(4) = 63 45a+4b+3c=1625(6r)+4(3r)+3(4r)=16254r=162r=3a=18b=9c=12a-b+c=21 (1) 63 4 (2)21

11.3a=2b2c=3babc= 18

3a=2bab = 232c=3bbc = 23 a b c 2 3 2 3 4 6 9 8 1218 8 12

12.xyzxy=43yz=25 [xyz]=240 (1)xyz= (2)x+2y+3z=

x y z 4 3 2 5 8 6 15 x=8ry=6rz=15r[8r6r15r]=240120r=240r=2x=16y=12z=30x+2y+3z=130 (1) 8615 (2)130

13.3040 323 2

xyz 3x=2y 3y=2z x y z 2 3 2 3 4 6 9 x=4ry=6rz=9r4r+6r+9r=3040r=1609r=14401440

14.3451296

3x=4y 5y=12zxyz 96z=8(12z)=8(5y)=40y=30x30

15.ABCA=xoB=yoC=zo 2x3y=892yz=65 2x3y=89xy = 432yz = 65yz = 35xy z = 43 5x=4ry=3rz=5r4r+3r+5r=180or=15oA=60oB=45oC=75oA=60oB=45oC=75o

16.abc=235a+b+c=100ax=4b-2cx=

a=2rb=3rc=5r2r+3r+5r=100r=10a=20b=30c=5020x=120-100x=11

17.10x-y=3x+4y(x+z)z=31xyz=

10x-y=3x+4y7x=5yxy = 57(x+z)z=313z=x+zx=2zxz = 21 x y z 5 7 2 1 1014 5 10145

18.1724

ab(a-b)(a+b)ab = 1724 a-b=ra+b=7rab=24r(a-b)+(a+b)=r+7ra=4rb=3r(4r)(3r)=24rr=2a=8b=686

19.(x-2y)(2x-3z)(2y+z)=123xyz=

x-2y=r2x-3z=2r2y+z=3r(3) 3 + (2) 2x+6y=11r(4)(1) 3 + (4) 5x=14rx=14r/5y=9r/10z=6r/5xyz = 2891228912

20.xyz02x+y-7z=x+y-5z=0xyz=

(1)-(2) x-2z=0x=2z(2) 2 +(1) y-3z=0y=3zxyz = 2z 3zz = 231 231