1. Show that: log⁡xy+log⁡yz+log⁡zx=0\log \frac{x}{y} + \log \frac{y}{z} + \log \frac{z}{x} = 0 2. Show that: 1log⁡624+1log⁡1224+1log⁡824=2\frac{1}{\log_6 24} + \frac{1}{\log_{12} 24} + \frac{1}{\log_8 24} = 2 3. If x=log⁡cabx = \log_c ab, y=log⁡abcy = \log_a bc, z=log⁡bcaz = \log_b ca, prove that: 11+x+11+y+11+z=1\frac{1}{1 + x} + \frac{1}{1 + y} + \frac{1}{1 + z} = 1 4. Prove that: 2log⁡67+12log⁡8116+log⁡19627=log⁡122\log\frac{6}{7} + \frac{1}{2}\log\frac{81}{16} + \log\frac{196}{27} = \log 12

Answer: All four logarithmic statements are proven: 1. log⁡(xy)+log⁡(yz)+log⁡(zx)=0\log\left(\frac{x}{y}\right) + \log\left(\frac{y}{z}\right) + \log\left(\frac{z}{x}\right) = 0 2. 1log⁡624+1log⁡1224+1log⁡824=2\frac{1}{\log_6 24} + \frac{1}{\log_{12} 24} + \frac{1}{\log_8 24} = 2 3. 11+x+11+y+11+z=1\frac{1}{1 + x} + \frac{1}{1 + y} + \frac{1}{1 + z} = 1 4. 2log⁡(67)+12log⁡(8116)+log⁡(19627)=log⁡122\log\left(\frac{6}{7}\right) + \frac{1}{2}\log\left(\frac{81}{16}\right) + \log\left(\frac{196}{27}\right) = \log 12

Step-by-step solution

Step 1: Solve Question 1 using Logarithmic Product Rule

We use the product property of logarithms, log⁡(a)+log⁡(b)+log⁡(c)=log⁡(abc)\log(a) + \log(b) + \log(c) = \log\text{(abc)}. Multiplying the three arguments gives xy×yz×zx=1\frac{x}{y} \times \frac{y}{z} \times \frac{z}{x} = 1. Since log⁡(1)=0\log(1) = 0, the sum evaluates directly to 00.

Step 2: Solve Question 2 using Base-Change Property

Applying the reciprocal base property 1log⁡ba=log⁡ab\frac{1}{\log_b a} = \log_a b, the expression becomes log⁡246+log⁡2412+log⁡248\log_{24} 6 + \log_{24} 12 + \log_{24} 8. Now all logarithms share the common base 2424, so we combine them by multiplying their arguments.

Step 3: Evaluate the Product for Question 2

Multiplying the arguments gives 6×12×8=5766 \times 12 \times 8 = 576. Since 576=242576 = 24^2, we simplify log⁡24(242)\log_{24}(24^2) to 2×1=22 \times 1 = 2, proving the given statement.

Step 4: Solve Question 3: Simplify Denominators

We rewrite 11 as log⁡cc\log_c c. Adding x=log⁡c(ab)x = \log_c(ab) yields 1+x=log⁡c(abc)1 + x = \log_c\text{(abc)}. Taking the reciprocal gives 11+x=log⁡abcc\frac{1}{1 + x} = \log_{abc} c. By identical symmetry, 11+y=log⁡abca\frac{1}{1 + y} = \log_{abc} a and 11+z=log⁡abcb\frac{1}{1 + z} = \log_{abc} b.

Step 5: Sum the Symmetrical Terms for Question 3

We add the three simplified fractions together: log⁡abcc+log⁡abca+log⁡abcb\log_{abc} c + \log_{abc} a + \log_{abc} b. Using the product rule, this equals log⁡abc(abc)\log_{abc}\text{(abc)}, which equals 11.

Step 6: Solve Question 4: Apply Power Rule and Combine

Using the power rule klog⁡(u)=log⁡(uk)k \log(u) = \log(u^k), we rewrite the terms as log⁡(3649)\log\left(\frac{36}{49}\right), log⁡(94)\log\left(\frac{9}{4}\right), and log⁡(19627)\log\left(\frac{196}{27}\right). Then, we combine them into a single logarithm using the product rule.

Step 7: Simplify Fractions for Question 4

Cancelling common factors: 19649=4\frac{196}{49} = 4, 364=9\frac{36}{4} = 9, and 9×427=3627=43\frac{9 \times 4}{27} = \frac{36}{27} = \frac{4}{3}. Multiplying 9×13×4=129 \times \frac{1}{3} \times 4 = 12. Therefore, the expression simplifies to log⁡12\log 12.

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