Logarithms Concise Class-9th ICSE Mathematics Selina Publications Solutions Chapter-8. We provide step by step Solutions of Exercise / lesson-8 Logarithms for ICSE Class-9 Concise Selina Mathematics by R K Bansal.
Our Solutions contain all type Questions with Exe-8 A, Exe-8 B, Exe-8 C, Exe-8 D and Exe-8 E to develop skill and confidence. Visit official Website CISCE for detail information about ICSE Board Class-9 Mathematics .
Logarithms Concise Class-9th ICSE Mathematics Selina Publications Solutions Chapter-8 by RK Bansal
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Exercise 8 A , Logarithms Concise Class-9th ICSE Mathematics Selina Publications Solutions
Question 1
Express each of the following in logarithmic form:
(i) 53 = 125
(ii) 3-2 = …….
(iii) 10-3 = 0.001
(iv) ………
Answer
Question 2
Express each of the following in exponential form:
(i) logg 0.125 = -1
(ii) log100.01 = -2
(iii) logaA = x
(iv) log101 = 0
Answer
Question 3
Solve for x: log10 x = -2.
Answer
Question 4
Find the logarithm of:
(i) 100 to the base 10
(ii) 0.1 to the base 10
(iii) 0.001 to the base 10
(iv) 32 to the base 4
(v) 0.125 to the base 2
(vi) 1/16 to the base 4
(vii) 27 to the base 9
(viii) 1/81 to the base 27
Answer
Question 5
State, true or false:
(i) If log10 x = a, then 10x = a.
(ii) If xy = z, then y = logzx.
(iii) log2 8 = 3 and log8 = 2 = 1/3
Answer
Question 6
Find x, if:
(i) log3 x = 0
(ii) logx 2 = -1
(iii) log9243 = x
(iv) log5 (x – 7) = 1
(v) log432 = x – 4
(vi) log7 (2x2 – 1) = 2
Answer
Question 7
Evaluate:
(i) log10 0.01
(ii) log2 (1 ÷ 8)
(iii) log5 1
(iv) log5 125
(v) log16 8
(vi) log0.5 16
Answer
Question 8
If loga m = n, express an – 1 in terms in terms of a and m.
Answer
Question 9
Given log
(i)…………
(ii)……………
Answer
Question 10
If log …………….
Answer
Question 11
Solve for X ……………..
Answer
Question 12
If log (x2 – 21) = 2, show that x
= ± 11.
Answer
Selina Publications Solutions Logarithms Concise Class-9th ICSE Mathematics Exercise 8 B
Question 1
Express in terms of log 2 and log 3:
(i) log 36
(ii) log 144
(iii) log 4.5
(iv) ……..
(v) ………… …..
Answer
Question 2
Express each of the following in a form free from logarithm:
(i) 2 log x – log y = 1
(ii) 2 log x + 3 log y = log a
(iii) a log x – b log y = 2 log 3
Answer
Question 3
Evaluate ……….
(i)………………..
(ii) ………………
(iii)……………
Answer
Question 4
Prove that:
…………………….
Answer
Question 5
Find x, if:
x – log 48 + 3 log 2 = 1/3 log 125 – log 3.
Answer
Question 6
Express log102 + 1 in the form of log10x.
Answer
Question 7
Solve for x:
(i) log10 (x – 10) = 1
(ii) log (x2 – 21) = 2
(iii) log (x – 2) + log (x + 2) = log 5
(iv) log (x + 5) + log (x – 5)
= 4 log 2 + 2 log 3
Answer
Question 8
Solve for x:
(i)………….
(ii)……………..
(iii)……………..
(iv)………………
Answer
Question 9
Given log x = m + n and log y = m – n, express the value of log ….. in terms of m and n.
Answer
Question 10
State, true or false:
(i) log 1 log 1000 = 0
(ii) ……………………
(iii) If then x = 2
(iv) log x log y = log x + log y
Answer
Question 11
If log102 = a and log103 = b; express each of the following in terms of ‘a’ and ‘b’:
(i) log 12(ii) log 2.25(iii) log ….
(iv) log 5.4(v) log 60(iv) log …….
Answer
Question 12
If log 2 = 0.3010 and log 3 = 0.4771; find the value of:
(i) log 12(ii) log 1.2(iii) log 3.6
(iv) log 15(v) log 25(vi) 2/3 log 8
Answer
Question 13
Given 2 log10 x + 1 = log10 250, find :
(i) x(ii) log10 2x
Answer
Question 14
Given 3 …………………..term of x .
Answer
Question 15
If x = …………………………….a , b and c .
Answer
Question 16
If 3 ……………………………find x .
Answer
Exercise 8 C, Logarithms Concise Class-9th ICSE Mathematics Selina Publications Solutions
Question 1
If log10 8 = 0.90; find the value of:
(i) log10 4
(ii) log ………
(iii) log 0.125
Answer
Question 2
f log 27 = 1.431, find the value of :
(i) log 9
(ii) log 300
Answer
Question 3
If log10 a = b, find 103b – 2 in terms of a.
Answer
Question 4
If log5 x = y, find 52y+ 3 in terms of x.
Answer
Question 5
Given: log3 m = x and log3 n = y.
(i) Express 32x – 3 in terms of m.
(ii) Write down 31 – 2y + 3x in terms of m and n.
(iii) If 2 log3 A = 5x – 3y; find A in terms of m and n.
Answer
Question 6
Simplify:
(i) log (a)3 – log a
(ii) log (a)3 +log a
Answer
Question 7
If log (a + b) = log a + log b, find a in terms of b.
Answer
Question 8
Prove that:
(i) (log a)2 – (log b)2 = log a/b . Log (ab)
(ii) If a log b + b log a – 1 = 0, then ba. ab = 10
Answer
Question 9
(i) If log (a + 1) = log (4a – 3) – log 3; find a.
(ii) If 2 log y – log x – 3 = 0, express x in terms of y.
(iii) Prove that: log10 125 = 3(1 – log102).
Answer
Question 10
Give log x……………….of log ………..
Answer
Question 11
Give log x……………….find x .
Answer
Solutions of Logarithms Concise Class-9th ICSE Mathematics Selina Publications for Exercise 8 D
Question 1
If 3/2 log a + 2/3 log b – 1 = 0, find the value of a9.b4.
Answer
Question 2
If x = 1 + log 2 – log 5, y = 2 log3 and z = log a – log 5; find the value of a if x + y = 2z.
Answer
Question 3
If x = log 0.6; y = log 1.25 and z = log 3 – 2 log 2, find the values of:
(i) x+y- z (ii) 5x + y – z
Answer
Question 4
If a2 = log x, b3 = log y and 3a2 – 2b3 = 6 log z, express y in terms of x and z.
Answer
Question 5
If log ……………….. (log a + log b), show that: a2 + b2 = 6ab.
Answer
Question 6
If a2 + b2 = 23ab, show that:
log …………….. (log a + log b).
Answer
Question 7
If m = log 20 and n = log 25, find the value of x, so that: 2 log (x – 4) = 2 m – n.
Answer
Question 8
Solve for x and y ; if x > 0 and y > 0;log xy = log x/y + 2 log 2 = 2.
Answer
Question 9
Find x, if:
(i) logx 625 = -4
(ii) logx (5x – 6) = 2
Answer
Question 10
If p =log ……………………………2p-q .
Answer
Question 11
If log………………. x and y .
Answer
Question 12
Given ……………. x and y .
Answer
Question 13
Given log10x = 2a and log10y = ……
(i) Write 10a in terms of x.
(ii) Write 102b + 1 in terms of y.
(iii) If …………….., express P in terms of x and y.
Answer
Question 14
Solve:
log5(x + 1) – 1 = 1 + log5(x – 1).
Answer
Question 15
Solve for x, if:
…………………
Answer
Question 16
if ……………………….x and y .
Answer
Question 17
Give x …………………………find
(i)……………
(ii)……………
Answer
Question 18
Solve for ……………
Answer
Question 19
Evaluate
(i)……….
(ii)…………..
(iii)…………..
Answer
Question 20
Show that
…………….
Answer
Question 21
If log …………find x .
Answer
Question 22
Evaluate ………………….
Answer
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