Math Problem Statement

Determine the exact solution of the equation.

3ˣ⁺²=5²ˣ⁻¹

Solution

We are tasked with solving the equation:

3x+2=52x13^{x+2} = 5^{2x-1}

Step 1: Take the natural logarithm of both sides

Applying the natural logarithm (ln) to both sides of the equation allows us to bring down the exponents.

ln(3x+2)=ln(52x1)\ln(3^{x+2}) = \ln(5^{2x-1})

Step 2: Use the logarithmic identity ln(ab)=bln(a)\ln(a^b) = b \ln(a)

This identity lets us move the exponents to the front:

(x+2)ln(3)=(2x1)ln(5)(x+2) \ln(3) = (2x-1) \ln(5)

Step 3: Distribute the logarithms

Now, distribute the logarithms on both sides:

xln(3)+2ln(3)=2xln(5)ln(5)x \ln(3) + 2 \ln(3) = 2x \ln(5) - \ln(5)

Step 4: Gather the terms with xx on one side

Move all terms involving xx to one side, and the constant terms to the other side:

xln(3)2xln(5)=ln(5)2ln(3)x \ln(3) - 2x \ln(5) = - \ln(5) - 2 \ln(3)

Factor out xx on the left-hand side:

x(ln(3)2ln(5))=ln(5)2ln(3)x (\ln(3) - 2 \ln(5)) = - \ln(5) - 2 \ln(3)

Step 5: Solve for xx

Now, isolate xx:

x=ln(5)2ln(3)ln(3)2ln(5)x = \frac{- \ln(5) - 2 \ln(3)}{\ln(3) - 2 \ln(5)}

Final Answer:

Thus, the exact solution for xx is:

x=ln(5)2ln(3)ln(3)2ln(5)x = \frac{- \ln(5) - 2 \ln(3)}{\ln(3) - 2 \ln(5)}


Would you like further details or clarification? Here are 5 related questions to explore:

  1. How would the solution change if the base of the exponents were the same?
  2. What would the solution be if we used logarithms with a different base (e.g., base 10)?
  3. How can we approximate this solution using numerical methods or a calculator?
  4. How do logarithmic properties simplify more complex exponential equations?
  5. Can this method be applied to equations involving more than two exponential terms?

Tip: When solving equations with exponents, logarithms are a powerful tool to help simplify and solve for the unknown variable.

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Math Problem Analysis

Mathematical Concepts

Exponential Equations
Logarithms
Algebra

Formulas

ln(a^b) = b * ln(a)
x = (-ln(5) - 2 * ln(3)) / (ln(3) - 2 * ln(5))

Theorems

Logarithmic Identity

Suitable Grade Level

Grades 10-12