kode soal 221
TRANSCRIPT
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Kode soal 221
1. Jika 8m = 27, maka 2.4m – 2m+1 = …
A. 12
B. 15
C. 18
D. 21
E. 24
PEMBAHASAN :
8m = 27
(23)m = 33
2m = 3
2.4m – 2m+1 = 2.22m – 2.2m
= 2.(2m)2 – 2.2m
= 2.(3)2 – 2.3
= 18 – 6
= 12
JAWABAN : A
2. Jika 3log a + 2(3log b) = 1 a! 3log b + 2(3log a) = 2, maka !ilai ab
aala" …
A. 2
B. 3
C. 6
D. #
E. 12
PEMBAHASAN :
3log a + 2(3log b) = 1
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3log a + 3log b2 = 1
3log ab2 = 1
ab2 = 31
a = 3$b2 … (i)
3log b + 2(3log a) = 2
3log b + 3log a2 = 2
3log a2b = 2
a2b = 32 … (ii)
%&b%'i'&%i *% (i) k *% (ii), %"i!gga
(3$b2)2b = 32
(32$b4)b = 32
32$32 = b3
1 = b
a = 3$b2
= 3$12
= 3
maka a.b = 3.1 = 3
JAWABAN : B
3. *%amaa! k&a*a' 2 – (a + 1) + a = - mm&!ai aka*/aka* 1 a! 2.
Jika 1(2 – 1) = 3, maka !ilai a aala" …
A. 4
B. 3
C. 2
D. /3
E. /4
PEMBAHASAN :
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0 2 – (a + 1) + a = -
1 + 2 = /b$a = a + 1
1 . 2 = $a = a
1(2 – 1) = 3
12 – 1 = 3
a – 1 = 3
1 = a – 3
1 + 2 = a + 1
(a – 3) + 2 = a + 1
2 = 4
1 . 2 = a
1 = a$4
1 = a – 3
a$4 = a – 3
a = 4a – 12
a = 3
JAWABAN : B
4. Jika g*aik &!g%i k&a*a' () = a2 + b + mm&!ai 'i'ik &!ak
(8, 4) a! mmo'o!g %&mb&/ !ga'i, maka …
A. a -, b -, a! -
B. a -, b -, a! -
C. a -, b -, a! -
D. a -, b -, a! -
E. a -, b -, a! -
PEMBAHASAN :
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0a*!a 'i'ik &!ak b*aa aa %&mb&/ o%i'i a! k&*a mmo'o!g
%&mb&/ !ga'i maka aa' ia%'ika! mmb!'&k k&*a '*b&ka kbaa"
%"i!gga a -.
B*a%a*ka! ak'a ia'a%, aa' iambil k%im&la! ba"a k&*a mmo'o!g
i %&mb&/ o%i'i %"i!gga i*ol" -.
() = 2a + b = -
(8) = 16a + b = -
b = /16a
ka*!a a - a! mi%al –a = , i*ol"
b = 16
9ai b "a*&%la" o%i'i a'a& b -
JAWABAN : E
5. :b& m!aa'ka! o'o!ga! "a*ga %b%a* 25; a*i 'o'al mblia! ba*a!g
i %&a'& 'oko.
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= 1-; (-.75 )
= -.1 -.75
"a*ga a!g "a*&% ibaa* = "a*ga %'la" i i%ko! + a9ak
= -.75 + -.1 -.75
= (1 + -.1) -.75
= (1.1 -.75)
JAWABAN : E
6. Jika 1 a 2, maka %m&a !ilai a!g mm!&"i *'iak%amaa!
- aala" …
A. /3 a'a& -
B. /3 a'a& /2
C. /2 a'a&
D. /3 -
E. /2 -
PEMBAHASAN :
D = b2 – 4a
= (2a)2 – 4(/1)(/6)
= 4a2 – 24
ka*!a 1 a 2, maka 4a2 – 24 -
a'a& D -, a*'i!a mbila!g 'iak mmiliki aka*2 *iil.
2 + 3 = ( + 3)
= - a'a& = /3
b*a%a*ka! ga*i% bila!ga! i*ol" /3 -
JAWABAN : D
7. :i! i!gi! mmbli %a !ga! "a*ga &a kali %a a!g i!gi! ibli
!il. !il 'la" mmiliki > 15-.---,-- a! aka! m!ab&!g > 3.---,--
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* mi!gg&. :i! 'la" mmiliki > 1--.---,-- a! aka! m!ab&!g >
1-.--- * mi!gg&. ?a*ga %a a!g aka! ibli !il aala" …
A. > 2--.---,--
B. > 3--.---,--
C. > 4--.---,--
D. > 5--.---,--
E. > 6--.---,--
PEMBAHASAN :
mi%al %a !il = a! %a :i! = :
! = 9&mla" mi!gg&
: = 2
1--.--- + 1-.--- ! = 2(15-.--- + 3.--- !)
1--.--- + 1-.--- ! = 3--.--- + 6.--- !
4.--- ! = 2--.---
! = 5-
"a*ga %a !il = 15-.--- + 3.--- !
= 15-.--- + 3.--- (5-)
= 15-.--- + 15-.---
= 3--.---
JAWABAN : B
8. Di%'*ib&%i b*a' bai la"i* i *&ma" %aki' A a! B aa' ili"a' aa
iag*am b*ik&'.
gamba* m!&%&l
B*a' baa! bai ika'aka! !o*mal aabila b*'a!a %aa' la"i* lbi" a*i
25-- g*am. Ba!ak bai !o*mal a!g la"i* i &a *&ma" %aki' '*%b&'
aala" …
A. 12
B. 32
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C. 44
D. 128
E. 172
PEMBAHASAN :
iag*am *'ama (>@ A) 6- a! 32
iag*am k&a (>@ B) 68 a! 12
9ai ba!ak bai a!g la"i* !o*mal i &a *&ma" %aki' aala" 6- + 32 +
68 + 12 = 172 bai
JAWABAN : E
9. ia!, *a'a/*a'a a! mo&% a*i a'a a!g '*i*i a*i a'a% ma'
bila!ga! a%li aala" 7. Jika %li%i" a!'a*a a'a '*b%a* a! a'a'*kil aala" 6, maka "a%il kali ma' a'a '*%b&' aala" …
A. 1864
B. 1#32
C. 1#6-
D. 1#76
E. 1#83
PEMBAHASAN :
Dik' = o = = 7
mi%al 4 bila!ga! a!g imak%& aala" a, b, a! (%&a"
'*&*&').
– a = 6 a = – 6
= = 7
b + = 14
=
7 =
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28 = 2 + 8
1- =
%"i!gga i*ol" a = 4
ka*!a o = 7 a! b + = 14, maka b = = 7
9ai a.b.. = 4.7.7.1- = 1#6-
JAWABAN : C
10. Jika , maka !ilai a a!g mm!&"i = /5 aala" …
A. 1
B. 1$2
C. /1
D. /3$2
E. /2
PEMBAHASAN :
=
=
=
/5 =
/5(a + 2) = 2a – 3
/5a – 1- = 2a – 3
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7a = /7
a = /1
JAWABAN : C
11. Jika A = , B = a! AB = , maka !ilai a +
aala" …
A. -
B. 1
C. 2
D. 5
E. #
PEMBAHASAN :
AB =
=
kolom 1 ba*i% 1 3 = 2a – b + 4
kolom 2 ba*i% 1 1 = 2a + b
b = 1 – 2a
3 = 2a – (1 – 2a) + 4
3 = 4a + 4 – 1
4 = 4a + 4
1 = a +
JAWABAN : B
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12. Dik'a"&i a, b, a! b*'&*&'/'&*&' aala" %&k& k/2, k/4, a! k/6
%&a'& ba*i%a! a*i'ma'ika. Jika = 4, maka !ilai b aala" …
A. /4
B. /2
C. 1
D. 2
E. 4
PEMBAHASAN :
mi%al %&k& aal = a! ba =
! = + (! – 1)
2 = + = a
4 = + 3 = b
6 = + 5 =
= 4
= 4
= 4
3 + # = 4 + 12 + 4
+ 3 = /4
b = /4
JAWABAN : A
13. Dik'a"&i *' gom'*i 'ak "i!gga &1 + &2 + &3 + … . Jika *a%io *'
'*%b&' aala" * !ga! /1 * 1, & 2 + &4 + &6 + … = 4, a! &2 + &4 =
15$4, maka !ilai * aala" …
A. a'a&
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B. a'a&
C. a'a&
D. a'a&
E. a'a&
PEMBAHASAN :
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14. a*abola = 2 – (k + 2) + 2k mmo'o!g %&mb&/ i (-, ) a! mmo'o!g
%&mb&/ i (a, -) a! (b, -). Jika a + 2, , a! a + 2b mmb!'&k
ba*i%a! a*i'ma'ika, maka !ilai k aala" …
A. 3
B. 2
C. 1
D. 1$3
E. /1$3
PEMBAHASAN :
'i'ik (-, )
= (-)2 – (k + 2)(-) + 2k
= 2k
'i'ik o'o!g
1,2 =
=
=
=
=
=
1 = (k + 2) + (k – 2) = k
2 = (k + 2) – (k – 2) = 2
ka*!a a*abola mmo'o!g %&mb&/ i (a, -) a! (b, -) maka 1 = a = k
a'a& 2 = b = 2
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ba*i%a! a*i'ma'ika a + 2, , a! a + 2b
– (a + 2) = (a + 2b) –
2 = (a + 2b) + (a + 2)
2 = 2a + 2b + 2
= a + b + 1
2k = k + 2 + 1
k = 3
JAWABAN : A
15. 0o k&o! "aia" &!'&k bla!9a aa %&a'& 'oko %alaa! b*b!'&k
bila!ga! a!g i%&%&! a*i a!gka 1, 3, 3, 6, #. Jika k&o!/k&o!
'*%b&' i%&%&! b*a%a*ka! ko!a m&lai a*i a!g '*kil %amai!ga! a!g '*b%a*, maka k&o! !ga! ko k&*a!g a*i 63--- %ba!ak
…
A. 51
B. 4-
C. 3#
D. 36
E. 24