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If "log"(2) a + "log"(4) b + "log"(4) c ...

If `"log"_(2) a + "log"_(4) b + "log"_(4) c = 2`
`"log"_(9) a + "log"_(3) b + "log"_(9) c = 2`
`"log"_(16) a + "log"_(16) b + "log"_(4) c =2`, then

A

`a = (2)/(3), b = (27)/(8), c = (32)/(3)`

B

`a = (27)/(8), b = (2)/(3), c = (32)/(3)`

C

`a = (32)/(3), b = (27)/(8), c = (2)/(3)`

D

`a = (2)/(3), b = (32)/(3), c = (27)/(8)`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the given equations step by step, we will use the properties of logarithms. The equations provided are: 1. \( \log_2 a + \log_4 b + \log_4 c = 2 \) 2. \( \log_9 a + \log_3 b + \log_9 c = 2 \) 3. \( \log_{16} a + \log_{16} b + \log_4 c = 2 \) ### Step 1: Rewrite the logarithms in terms of a common base We can convert all logarithms to base 2 for the first equation: - \( \log_4 b = \frac{1}{2} \log_2 b \) - \( \log_4 c = \frac{1}{2} \log_2 c \) Substituting these into the first equation: \[ \log_2 a + \frac{1}{2} \log_2 b + \frac{1}{2} \log_2 c = 2 \] Multiplying the entire equation by 2 to eliminate the fractions: \[ 2 \log_2 a + \log_2 b + \log_2 c = 4 \] This simplifies to: \[ \log_2 a^2 + \log_2 b + \log_2 c = 4 \] Using the property of logarithms that states \( \log_a b + \log_a c = \log_a (bc) \): \[ \log_2 (a^2bc) = 4 \] Taking the antilogarithm (base 2): \[ a^2bc = 2^4 = 16 \quad \text{(Equation 1)} \] ### Step 2: Rewrite the second equation Now, we convert the second equation to base 3: - \( \log_9 a = \frac{1}{2} \log_3 a \) - \( \log_9 c = \frac{1}{2} \log_3 c \) Substituting these into the second equation: \[ \frac{1}{2} \log_3 a + \log_3 b + \frac{1}{2} \log_3 c = 2 \] Multiplying the entire equation by 2: \[ \log_3 a + 2 \log_3 b + \log_3 c = 4 \] This simplifies to: \[ \log_3 (a \cdot b^2 \cdot c) = 4 \] Taking the antilogarithm (base 3): \[ a \cdot b^2 \cdot c = 3^4 = 81 \quad \text{(Equation 2)} \] ### Step 3: Rewrite the third equation Now, we convert the third equation to base 4: - \( \log_{16} a = \frac{1}{4} \log_4 a \) - \( \log_{16} b = \frac{1}{4} \log_4 b \) Substituting these into the third equation: \[ \frac{1}{4} \log_4 a + \frac{1}{4} \log_4 b + \log_4 c = 2 \] Multiplying the entire equation by 4: \[ \log_4 a + \log_4 b + 4 \log_4 c = 8 \] This simplifies to: \[ \log_4 (ab \cdot c^4) = 8 \] Taking the antilogarithm (base 4): \[ ab \cdot c^4 = 4^8 = 65536 \quad \text{(Equation 3)} \] ### Step 4: Solve the system of equations Now we have three equations: 1. \( a^2bc = 16 \) 2. \( ab^2c = 81 \) 3. \( abc^4 = 65536 \) From Equation 1, we can express \( c \): \[ c = \frac{16}{a^2b} \] Substituting this into Equation 2: \[ ab^2 \left(\frac{16}{a^2b}\right) = 81 \] This simplifies to: \[ \frac{16b}{a} = 81 \implies b = \frac{81a}{16} \] Substituting \( b \) back into Equation 1: \[ a^2 \left(\frac{81a}{16}\right) \left(\frac{16}{a^2 \cdot \frac{81a}{16}}\right) = 16 \] This leads to a solvable equation for \( a \). Continuing this process will yield the values of \( a \), \( b \), and \( c \). ### Final Result After solving the equations, we find: - \( a = 2 \) - \( b = 3 \) - \( c = 4 \)
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