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If 5^(3x^(2)"log"(10)2) = 2^((x + (1)/(2...

If `5^(3x^(2)"log"_(10)2) = 2^((x + (1)/(2))"log"_(10) 25)`, then x equals to

A

`1, -(1)/(3)`

B

1

C

`1, -(1)/(2)`

D

`-(1)/(3), 1`

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The correct Answer is:
To solve the equation \( 5^{3x^2 \log_{10} 2} = 2^{(x + \frac{1}{2}) \log_{10} 25} \), we can follow these steps: ### Step 1: Rewrite the Right-Hand Side We know that \( \log_{10} 25 = \log_{10} (5^2) = 2 \log_{10} 5 \). Therefore, we can rewrite the right-hand side as: \[ 2^{(x + \frac{1}{2}) \cdot 2 \log_{10} 5} = 2^{(2x + 1) \log_{10} 5} \] ### Step 2: Apply the Logarithmic Identity Using the property \( a^{\log_b x} = x^{\log_b a} \), we can rewrite both sides: \[ 5^{3x^2 \log_{10} 2} = (2^{(2x + 1)})^{\log_{10} 5} \] This gives us: \[ 5^{3x^2 \log_{10} 2} = 5^{(2x + 1) \log_{10} 2} \] ### Step 3: Equate the Exponents Since the bases are the same, we can set the exponents equal to each other: \[ 3x^2 \log_{10} 2 = (2x + 1) \log_{10} 2 \] ### Step 4: Simplify the Equation Assuming \( \log_{10} 2 \neq 0 \) (which is true), we can divide both sides by \( \log_{10} 2 \): \[ 3x^2 = 2x + 1 \] ### Step 5: Rearrange into Standard Quadratic Form Rearranging gives us: \[ 3x^2 - 2x - 1 = 0 \] ### Step 6: Solve the Quadratic Equation We can use the quadratic formula \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \) where \( a = 3, b = -2, c = -1 \): \[ x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4 \cdot 3 \cdot (-1)}}{2 \cdot 3} \] \[ x = \frac{2 \pm \sqrt{4 + 12}}{6} \] \[ x = \frac{2 \pm \sqrt{16}}{6} \] \[ x = \frac{2 \pm 4}{6} \] ### Step 7: Calculate the Roots Calculating the two possible values for \( x \): 1. \( x = \frac{6}{6} = 1 \) 2. \( x = \frac{-2}{6} = -\frac{1}{3} \) ### Step 8: Verify the Solutions We need to check if both values satisfy the original equation. 1. For \( x = 1 \): \[ LHS = 5^{3 \cdot 1^2 \log_{10} 2} = 5^{3 \log_{10} 2} = (2^{3})^{\log_{10} 5} = 2^{3 \log_{10} 5} \] \[ RHS = 2^{(1 + \frac{1}{2}) \log_{10} 25} = 2^{\frac{3}{2} \cdot 2 \log_{10} 5} = 2^{3 \log_{10} 5} \] Both sides are equal. 2. For \( x = -\frac{1}{3} \): \[ LHS = 5^{3 \left(-\frac{1}{3}\right)^2 \log_{10} 2} = 5^{\log_{10} 2} \] \[ RHS = 2^{\left(-\frac{1}{3} + \frac{1}{2}\right) \log_{10} 25} = 2^{\frac{1}{6} \cdot 2 \log_{10} 5} = 2^{\frac{1}{3} \log_{10} 5} \] Both sides are equal. ### Final Answer Thus, the values of \( x \) that satisfy the equation are: \[ x = 1 \quad \text{and} \quad x = -\frac{1}{3} \]
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OBJECTIVE RD SHARMA ENGLISH-LOGARITHMS-Exercise
  1. If x^(2"log"(10)x) = 1000x, then x equals to

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  2. If "log"(10)5 =x, " then log"(5) 1250 equals to

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  3. If 5^(3x^(2)"log"(10)2) = 2^((x + (1)/(2))"log"(10) 25), then x equals...

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  4. If "log"(x) (4x^("log"(5)x) + 5) = 2 "log"(5)x, then x equals to

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  5. The equation "log"(e)x + "log"(e)(1+x) =0 can be written as

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  6. If a =log3(5) and b =log17( 25), which one of the following is correct...

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  7. If x ="log"(a)(bc), y ="log"(b)(ca) " and "z = "log"(c)(ab), then whi...

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  8. The value of "log"(2)"log"(2)"log"(4) 256 + 2 "log"(sqrt(2))2, is

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  10. If "log"(2) 7 = x, then x is:

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  11. If 2^((3)/("log"(3)x)) = (1)/(64), then x =

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  12. If a = 1 + log(x) yz, b = 1 + log(y) zx and c = 1 + log xy where x, ...

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  13. If (logx)/(a^2+a b+b^2)=(logy)/(b^2+b c+c^2)=(logz)/(c^2+c a+a^2), the...

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  14. If log(2a-3b)=loga-logb, then a=

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  15. If ("log"3)/(x-y) = ("log"5)/(y-z) = ("log" 7)/(z-x), " then " 3^(x+y)...

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  16. ("log"(2)a)/(3) = ("log"(2)b)/(4) = ("log"(2)c)/(5lambda) " and " a^(-...

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  17. if loga/(b-c)=logb/(c-a)=logc/(a-b) then find the value of a^ab^bc^c

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  20. Find the value of 7 log(16/15) + 5 log (25/24) + 3 log (81/80).

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