Solve Complex Fraction Equation: (1/x - 1/2)² = (9/4)(1/x - 1/3)²

Complex Fractions with Substitution Method

(1x12)2(1x13)2=94 \frac{(\frac{1}{x}-\frac{1}{2})^2}{(\frac{1}{x}-\frac{1}{3})^2}=\frac{9}{4}

Find X

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Find X
00:03 Extract the root
00:07 Taking a root always gives 2 options - positive and negative
00:13 Taking the root cancels out the squares
00:16 Extract the root for both numerator and denominator
00:24 The second option is of course the negative one
00:29 Let's start solving the positive option
00:34 Multiply by the reciprocal to eliminate the fractions
00:42 Make sure to open parentheses properly, multiply by each factor
00:51 Isolate X
00:55 Collect terms
01:01 This option is not logical, division by 0 is not allowed
01:04 Let's try to solve the second option (negative)
01:10 Multiply by the reciprocal to eliminate the fractions
01:15 Make sure to open parentheses properly, multiply by each factor
01:23 Isolate X
01:42 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

(1x12)2(1x13)2=94 \frac{(\frac{1}{x}-\frac{1}{2})^2}{(\frac{1}{x}-\frac{1}{3})^2}=\frac{9}{4}

Find X

2

Step-by-step solution

To solve this problem, we'll follow these steps:

  • Step 1: Expand and simplify the numerator (1x12)2 (\frac{1}{x} - \frac{1}{2})^2 .
  • Step 2: Expand and simplify the denominator (1x13)2 (\frac{1}{x} - \frac{1}{3})^2 .
  • Step 3: Set up the equation as a proportion and solve for x x .

Let’s work through each step:
Step 1: Using the formula for the square of a difference, expand the numerator:

(1x12)2=(1x)22(1x)(12)+(12)2=1x21x+14(\frac{1}{x} - \frac{1}{2})^2 = \left(\frac{1}{x}\right)^2 - 2\left(\frac{1}{x}\right)\left(\frac{1}{2}\right) + \left(\frac{1}{2}\right)^2 = \frac{1}{x^2} - \frac{1}{x} + \frac{1}{4}.

Step 2: Similarly, expand the denominator:

(1x13)2=(1x)22(1x)(13)+(13)2=1x223x+19(\frac{1}{x} - \frac{1}{3})^2 = \left(\frac{1}{x}\right)^2 - 2\left(\frac{1}{x}\right)\left(\frac{1}{3}\right) + \left(\frac{1}{3}\right)^2 = \frac{1}{x^2} - \frac{2}{3x} + \frac{1}{9}.

Step 3: Substitute these into the original equation and solve the proportion:

1x21x+141x223x+19=94\frac{\frac{1}{x^2} - \frac{1}{x} + \frac{1}{4}}{\frac{1}{x^2} - \frac{2}{3x} + \frac{1}{9}} = \frac{9}{4}.

Cross-multiply to clear the fractions:

4(1x21x+14)=9(1x223x+19)4\left(\frac{1}{x^2} - \frac{1}{x} + \frac{1}{4}\right) = 9\left(\frac{1}{x^2} - \frac{2}{3x} + \frac{1}{9}\right).

Simplifying both sides gives:

4(1x21x+14)=41x241x+14(\frac{1}{x^2} - \frac{1}{x} + \frac{1}{4}) = 4\frac{1}{x^2} - 4\frac{1}{x} + 1.

9(1x223x+19)=91x261x+19(\frac{1}{x^2} - \frac{2}{3x} + \frac{1}{9}) = 9\frac{1}{x^2} - 6\frac{1}{x} + 1.

Equating the expressions, we have:

41x241x+1=91x261x+14\frac{1}{x^2} - 4\frac{1}{x} + 1 = 9\frac{1}{x^2} - 6\frac{1}{x} + 1.

Subtract 1 from both sides and collect like terms:

41x+1=51x221x-4\frac{1}{x} + 1 = 5\frac{1}{x^2} - 2\frac{1}{x}.

21x51x2=0-2\frac{1}{x} - 5\frac{1}{x^2} = 0.

Factoring gives:

51x(x2)=05\frac{1}{x}(x - 2) = 0.

Therefore, the solution for x x should satisfy x2=0 x - 2 = 0 , so x=2.5 x = 2.5 .

Thus, the value of x x is 2.5\boxed{2.5}.

3

Final Answer

2.5

Key Points to Remember

Essential concepts to master this topic
  • Substitution: Let u=1x u = \frac{1}{x} to simplify complex fraction equations
  • Square Roots: When solving (ua)2(ub)2=k \frac{(u-a)^2}{(u-b)^2} = k , take square root of both sides first
  • Check: Substitute x=2.5 x = 2.5 back: both sides equal 94 \frac{9}{4}

Common Mistakes

Avoid these frequent errors
  • Expanding the squared terms instead of taking square roots first
    Don't expand (1x12)2 (\frac{1}{x} - \frac{1}{2})^2 and (1x13)2 (\frac{1}{x} - \frac{1}{3})^2 immediately = messy algebra with 1x2 \frac{1}{x^2} terms! This creates unnecessary complexity and calculation errors. Always take the square root of both sides first: 1x121x13=±32 \frac{\frac{1}{x} - \frac{1}{2}}{\frac{1}{x} - \frac{1}{3}} = \pm\frac{3}{2} .

Practice Quiz

Test your knowledge with interactive questions

Complete the corresponding expression for the denominator

\( \frac{12ab}{?}=1 \)

FAQ

Everything you need to know about this question

Why should I use substitution with u=1x u = \frac{1}{x} ?

+

Substitution makes the equation look simpler! Instead of working with 1x \frac{1}{x} everywhere, you get (u12)2(u13)2=94 \frac{(u-\frac{1}{2})^2}{(u-\frac{1}{3})^2} = \frac{9}{4} , which is easier to handle.

Should I take the square root of both sides first?

+

Yes! Since you have squares on both sides, taking square roots gives you: u12u13=±32 \frac{u-\frac{1}{2}}{u-\frac{1}{3}} = \pm\frac{3}{2} . This avoids messy expansion and is much faster.

Why do I get a ± when taking square roots?

+

When you take the square root of both sides of an equation, you must consider both positive and negative possibilities. This gives you two cases to solve, potentially leading to multiple solutions.

How do I solve the linear equation after taking square roots?

+

Cross-multiply to clear fractions! For u12u13=32 \frac{u-\frac{1}{2}}{u-\frac{1}{3}} = \frac{3}{2} , you get: 2(u12)=3(u13) 2(u-\frac{1}{2}) = 3(u-\frac{1}{3}) , then solve for u.

What if I get multiple values for u?

+

Remember that u=1x u = \frac{1}{x} , so you need to find x=1u x = \frac{1}{u} for each valid u-value. Check that your x-values don't make any denominator zero!

How do I verify my answer is correct?

+

Substitute x=2.5 x = 2.5 into the original equation. Calculate 1x=0.4 \frac{1}{x} = 0.4 , then check that both sides equal 94=2.25 \frac{9}{4} = 2.25 .

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Factorization questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations