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

Question

(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

Video Solution

Solution Steps

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 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}.

Answer

2.5