Math Problem Statement

Solve for all values of x log, base, 2, left parenthesis, 2, x, squared, minus, 2, x, right parenthesis, equals, 2 log 2 ​ (2x 2 −2x)= 2

Solution

We are given the equation:

log2(2x22x)=2\log_2(2x^2 - 2x) = 2

Step 1: Convert the logarithmic equation to an exponential form.

Using the logarithmic identity:

logb(A)=Cis equivalent toA=bC\log_b(A) = C \quad \text{is equivalent to} \quad A = b^C

In this case, the base b=2b = 2, and the equation becomes:

2x22x=222x^2 - 2x = 2^2

2x22x=42x^2 - 2x = 4

Step 2: Set the equation equal to zero.

Rearrange the equation to form a standard quadratic:

2x22x4=02x^2 - 2x - 4 = 0

Step 3: Simplify the quadratic equation.

Divide the entire equation by 2 to simplify:

x2x2=0x^2 - x - 2 = 0

Step 4: Factor the quadratic.

Factor the equation:

(x2)(x+1)=0(x - 2)(x + 1) = 0

Step 5: Solve for xx.

Set each factor equal to zero:

x2=0x=2x - 2 = 0 \quad \Rightarrow \quad x = 2

x+1=0x=1x + 1 = 0 \quad \Rightarrow \quad x = -1

Step 6: Check for extraneous solutions.

Since we are solving a logarithmic equation, we must ensure that the arguments of the logarithm are positive (the domain of the logarithm). The argument of the logarithm is 2x22x2x^2 - 2x. Substituting x=2x = 2 and x=1x = -1:

  • For x=2x = 2:

2(2)22(2)=84=4(positive)2(2)^2 - 2(2) = 8 - 4 = 4 \quad (\text{positive})

  • For x=1x = -1:

2(1)22(1)=2+2=4(positive)2(-1)^2 - 2(-1) = 2 + 2 = 4 \quad (\text{positive})

Both values of xx satisfy the domain of the logarithmic function.

Final Answer:

The solutions are:

x=2andx=1x = 2 \quad \text{and} \quad x = -1

Would you like more details or have any questions about the steps?

Here are 5 related questions for further practice:

  1. Solve log2(x23x)=1\log_2(x^2 - 3x) = 1.
  2. Solve log3(3x26x)=2\log_3(3x^2 - 6x) = 2.
  3. Find the domain of log2(3x2x)\log_2(3x^2 - x).
  4. Solve log4(x22x+1)=0\log_4(x^2 - 2x + 1) = 0.
  5. Solve log5(x24x+4)=1\log_5(x^2 - 4x + 4) = 1.

Tip: Always check if the arguments inside logarithmic functions are positive when solving logarithmic equations to avoid extraneous solutions.

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Math Problem Analysis

Mathematical Concepts

Logarithms
Quadratic Equations
Exponential Equations

Formulas

log_b(A) = C is equivalent to A = b^C
Quadratic equation: ax^2 + bx + c = 0

Theorems

Logarithmic to Exponential Conversion
Factoring Quadratic Equations

Suitable Grade Level

Grades 9-12