Simplify log 6 - log 15 + 2 log 5 and log (5/8) - 2 log (5/9) + log 40

Mathematics
Simplify log 6 - log 15 + 2 log 5 and log (5/8) - 2 log (5/9) + log 40

ScanSolve AI Answer

1(a)

Step 1: Start with the given equation.
logb=log15+2log5\log b = \log 15 + 2 \log 5

Step 2: Apply the power rule: nloga=log(an)n \log a = \log (a^n).
2log5=log(52)2 \log 5 = \log (5^2)
logb=log15+log(52)\log b = \log 15 + \log (5^2)

Step 3: Apply the product rule: loga+logc=log(ac)\log a + \log c = \log (a \cdot c).
logb=log(1552)\log b = \log (15 \cdot 5^2)

Step 4: Compute 52=255^2 = 25.
logb=log(1525)\log b = \log (15 \cdot 25)

Step 5: Compute 1525=37515 \cdot 25 = 375.
logb=log375\log b = \log 375

Step 6: If logb=log375\log b = \log 375, then b=375b = 375.
Final answer: b=375b = 375
375

2)

Step 1: Start with the given expression.
log532log37+log44\log \frac{5}{3} - 2 \log \frac{3}{7} + \log 44

Step 2: Apply the power rule to the second term: nloga=log(an)n \log a = \log (a^n).
2log37=log(37)2=log949-2 \log \frac{3}{7} = -\log \left( \frac{3}{7} \right)^2 = -\log \frac{9}{49}

Step 3: Apply the quotient rule to the negative log: log949=log499-\log \frac{9}{49} = \log \frac{49}{9}.
log53+log499+log44\log \frac{5}{3} + \log \frac{49}{9} + \log 44

Step 4: Apply the product rule for logs: loga+logb+logc=log(abc)\log a + \log b + \log c = \log (a \cdot b \cdot c).
log(5349944)\log \left( \frac{5}{3} \cdot \frac{49}{9} \cdot 44 \right)

Step 5: Simplify the argument step-by-step. First, 53499\frac{5}{3} \cdot \frac{49}{9}.
Numerator: 549=2455 \cdot 49 = 245
Denominator: 39=273 \cdot 9 = 27
2452744\frac{245}{27} \cdot 44

Step 6: Now multiply by 44.
24544=10780245 \cdot 44 = 10780
log1078027\log \frac{10780}{27}

Step 7: Check if 1078027\frac{10780}{27} simplifies (gcd of 10780 and 27 is 1).
Final answer: log1078027\log \frac{10780}{27}
\log \dfrac{10780{27}}

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