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Given that $9^{\frac{1}{2}} = 27^{x} + 3^{1+x}$ find the exact value of x. - Edexcel - GCSE Maths - Question 20 - 2019 - Paper 1

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Given-that-$9^{\frac{1}{2}}-=-27^{x}-+-3^{1+x}$-find-the-exact-value-of-x.-Edexcel-GCSE Maths-Question 20-2019-Paper 1.png

Given that $9^{\frac{1}{2}} = 27^{x} + 3^{1+x}$ find the exact value of x.

Worked Solution & Example Answer:Given that $9^{\frac{1}{2}} = 27^{x} + 3^{1+x}$ find the exact value of x. - Edexcel - GCSE Maths - Question 20 - 2019 - Paper 1

Step 1

Step 1: Convert to a Common Base

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Answer

We first express all terms using base 3. Recall that:

  • 9=329 = 3^2
  • 27=3327 = 3^3

Thus, we can rewrite the equation:

(32)12=(33)x+31+x\left(3^2\right)^{\frac{1}{2}} = \left(3^3\right)^{x} + 3^{1+x}

This simplifies to:

31=33x+31+x3^{1} = 3^{3x} + 3^{1+x}

Step 2

Step 2: Set Exponents Equal

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Answer

Now, we factor out the common term from the right side:

31=31+x(1+32x(1+x))3^{1} = 3^{1+x}(1 + 3^{2x - (1+x)})

This means we have:

31=31+x3^1 = 3^{1+x}

Equating the exponents gives:

1=1+x1 = 1 + x

Step 3

Step 3: Solve for x

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Answer

From the equation 1=1+x1 = 1 + x, we can solve for x:

x=0x = 0

Thus, the exact value of xx is:

x=0x = 0

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