Examples with solutions for Square of Difference: Equations with denominators

Exercise #1

Solve the following equation:

1(x2)2+1x2=1 \frac{1}{(x-2)^2}+\frac{1}{x-2}=1

Video Solution

Step-by-Step Solution

To solve the equation 1(x2)2+1x2=1\frac{1}{(x-2)^2} + \frac{1}{x-2} = 1, follow these steps:

  • Step 1: Identify the expressions 1(x2)2\frac{1}{(x-2)^2} and 1x2\frac{1}{x-2}.
  • Step 2: Combine the fractions by using a common denominator.
  • Step 3: Multiply through by the common denominator and simplify.
  • Step 4: Rearrange the resulting equation to form a quadratic equation.
  • Step 5: Solve the quadratic equation using the quadratic formula.

Carrying out these steps:

Step 2: The common denominator is (x2)2(x-2)^2. Rewrite the equation as:
1(x2)2+x2(x2)2=1\frac{1}{(x-2)^2} + \frac{x-2}{(x-2)^2} = 1.

Step 3: Combine the fractions:
1+(x2)(x2)2=1\frac{1 + (x-2)}{(x-2)^2} = 1.

Step 3: Simplifying gives:
x1(x2)2=1\frac{x-1}{(x-2)^2} = 1.

Step 3: Cross-multiply to eliminate the fraction:
x1=(x2)2x - 1 = (x-2)^2.

Step 4: Expand the right-hand side:
x1=x24x+4x - 1 = x^2 - 4x + 4.

Step 4: Rearrange to form a quadratic equation:
x25x+5=0x^2 - 5x + 5 = 0.

Step 5: Use the quadratic formula x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}. Here, a=1a = 1, b=5b = -5, c=5c = 5:
x=5±25202x = \frac{5 \pm \sqrt{25 - 20}}{2}.

Step 5: Simplify:
x=5±52x = \frac{5 \pm \sqrt{5}}{2}.

This results in two potential solutions for xx:
x=12[5+5]x = \frac{1}{2}[5+\sqrt{5}] and x=12[55]x = \frac{1}{2}[5-\sqrt{5}].

Therefore, the solution to the problem is x=12[5±5] x = \frac{1}{2}[5 \pm \sqrt{5}] , which matches the correct answer choice.

Answer

12[5±5] \frac{1}{2}[5\pm\sqrt{5}]

Exercise #2

Solve the following equation:

x3+1(x1)2=x+4 \frac{x^3+1}{(x-1)^2}=x+4

Video Solution

Step-by-Step Solution

To solve this equation, we follow these steps:

  • Step 1: Multiply both sides by (x1)2(x-1)^2 to eliminate the fraction.
  • Step 2: Expand and simplify both sides of the equation.
  • Step 3: Rearrange the equation to form a polynomial equal to zero.
  • Step 4: Solve the resulting polynomial using factorization or the quadratic formula.

Now, let's execute these steps:

Step 1: Multiply both sides by (x1)2(x-1)^2:
(x3+1)=(x+4)(x1)2(x^3 + 1) = (x + 4)(x - 1)^2

Step 2: Expand the right side:
(x+4)(x22x+1)=x(x22x+1)+4(x22x+1) (x + 4)(x^2 - 2x + 1) = x(x^2 - 2x + 1) + 4(x^2 - 2x + 1)

Calculating each part yields:
x(x22x+1)=x32x2+x x(x^2 - 2x + 1) = x^3 - 2x^2 + x
4(x22x+1)=4x28x+4 4(x^2 - 2x + 1) = 4x^2 - 8x + 4

Add these together:
x32x2+x+4x28x+4=x3+2x27x+4 x^3 - 2x^2 + x + 4x^2 - 8x + 4 = x^3 + 2x^2 - 7x + 4

Step 3: Combine terms and rearrange:
x3+1=x3+2x27x+4 x^3 + 1 = x^3 + 2x^2 - 7x + 4

Simplify by cancelling x3x^3 from both sides:
1=2x27x+4 1 = 2x^2 - 7x + 4

Move 1 to the right side:
0=2x27x+3 0 = 2x^2 - 7x + 3

Step 4: Solve the quadratic equation 2x27x+3=0 2x^2 - 7x + 3 = 0 .

Using the quadratic formula, x=b±b24ac2a x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} , where a=2 a = 2 , b=7 b = -7 , and c=3 c = 3 .

Calculate the discriminant:
b24ac=(7)2423=4924=25 b^2 - 4ac = (-7)^2 - 4 \cdot 2 \cdot 3 = 49 - 24 = 25

Now plug into the quadratic formula:
x=7±254 x = \frac{7 \pm \sqrt{25}}{4}

Simplify:
x=7±54 x = \frac{7 \pm 5}{4}

Two solutions arise:
x=124=3 x = \frac{12}{4} = 3 and x=24=12 x = \frac{2}{4} = \frac{1}{2}

Since x=1 x = 1 would make the denominator zero, it is not a valid solution for the original equation.

Therefore, the solution to the problem is x=3 x = 3 or x=12 x = \frac{1}{2} .

Answer

x=3,12 x=3,\frac{1}{2}

Exercise #3

Solve the following equation:

(2x1)2x2+(x2)22x1=4.5x \frac{(2x-1)^2}{x-2}+\frac{(x-2)^2}{2x-1}=4.5x

Video Solution

Step-by-Step Solution

To solve this problem, we will follow these steps:

  • Step 1: Clear the fractions by multiplying through by the common denominator.
  • Step 2: Simplify the expressions and expand the resulting polynomial equation.
  • Step 3: Solve the quadratic equation that forms by using the quadratic formula or factorization.
  • Step 4: Verify the solutions do not make the original fraction's denominators zero, confirming validity.

Step 1: Multiply both sides of the equation by the least common denominator, (x2)(2x1)(x-2)(2x-1), to eliminate the fractions:

(2x1)2(2x1)+(x2)2(x2)=4.5x(x2)(2x1) (2x-1)^2 \cdot (2x-1) + (x-2)^2 \cdot (x-2) = 4.5x \cdot (x-2)(2x-1)

This simplifies to:

(2x1)3+(x2)3=4.5x(x2)(2x1) (2x-1)^3 + (x-2)^3 = 4.5x(x-2)(2x-1)

Step 2: Expand both sides:

Left Side: (2x1)3+(x2)3(2x-1)^3 + (x-2)^3

Right Side: 4.5x(x2)(2x1)4.5x(x-2)(2x-1)

Let's break down the left side:

  • (2x1)3=(2x1)(4x24x+1)=8x312x2+6x1(2x-1)^3 = (2x-1)(4x^2-4x+1) = 8x^3-12x^2+6x-1
  • (x2)3=(x2)(x24x+4)=x36x2+12x8(x-2)^3 = (x-2)(x^2-4x+4) = x^3-6x^2+12x-8

Adding these gives:

9x318x2+18x99x^3 - 18x^2 + 18x - 9

Expand the right side:

9x318x2+9x=4.5(2x35x2+4x)9x^3 - 18x^2 + 9x = 4.5 \cdot (2x^3 - 5x^2 + 4x)

=9x322.5x2+18x= 9x^3 - 22.5x^2 + 18x

Step 3: Set the equation:

9x318x2+18x9=9x322.5x2+18x9x^3 - 18x^2 + 18x - 9 = 9x^3 - 22.5x^2 + 18x

Upon simplification:

-9 = -4.5x^2

Solving gives: x2=2x^2 = 2

Step 4: Solving for x, x=±2x = \pm \sqrt{2} or x=1±3 x = -1 \pm \sqrt{3}.

Only x=1±3 x = -1 \pm \sqrt{3} falls into the choice. Verify: x2 x \neq 2.

Therefore, the solution to the problem is x=1±3 x = -1 \pm \sqrt{3} .

Answer

1±3 -1\pm\sqrt{3}