Math Problem Statement

Solve the following equations: (a) e^(2x) − 3e^x + 2 = 0 (b) log(base2) 3 + log(base2) x = log(base2) 5 + log(base2)(x − 2)

Solution

Let's solve each equation step by step:

(a) e2x3ex+2=0e^{2x} - 3e^x + 2 = 0

Step 1: Substitute y=exy = e^x

This substitution simplifies the equation. Since e2x=(ex)2e^{2x} = (e^x)^2, we rewrite the equation as: y23y+2=0y^2 - 3y + 2 = 0

Step 2: Solve the quadratic equation

Now we solve the quadratic equation y23y+2=0y^2 - 3y + 2 = 0. Factoring gives: (y1)(y2)=0(y - 1)(y - 2) = 0 So, y=1y = 1 or y=2y = 2.

Step 3: Substitute back y=exy = e^x

Since y=exy = e^x, we have two cases:

  • ex=1e^x = 1, which gives x=ln(1)=0x = \ln(1) = 0.
  • ex=2e^x = 2, which gives x=ln(2)x = \ln(2).

Thus, the solutions to the first equation are: x=0orx=ln(2)x = 0 \quad \text{or} \quad x = \ln(2)


(b) log2(3)+log2(x)=log2(5)+log2(x2)\log_2(3) + \log_2(x) = \log_2(5) + \log_2(x - 2)

Step 1: Use the logarithmic property

Recall that logb(A)+logb(B)=logb(AB)\log_b(A) + \log_b(B) = \log_b(A \cdot B). Apply this property to both sides of the equation: log2(3x)=log2(5(x2))\log_2(3x) = \log_2(5(x - 2))

Step 2: Remove the logarithms

Since the logarithms have the same base, we can equate the arguments: 3x=5(x2)3x = 5(x - 2)

Step 3: Solve the linear equation

Expand the right-hand side: 3x=5x103x = 5x - 10 Rearrange the terms: 3x5x=10    2x=103x - 5x = -10 \implies -2x = -10 Solving for xx: x=5x = 5

Step 4: Check for extraneous solutions

We need to check that x2>0x - 2 > 0, which gives x>2x > 2. Since x=5x = 5, it satisfies this condition.

Thus, the solution to the second equation is: x=5x = 5


Final Solutions:

(a) x=0x = 0 or x=ln(2)x = \ln(2)

(b) x=5x = 5


Would you like any further details or explanations on any step?


Here are 5 related questions for further practice:

  1. Solve e3x4ex+3=0e^{3x} - 4e^x + 3 = 0.
  2. Solve log3(x2)=log3(5x)\log_3(x^2) = \log_3(5x).
  3. Solve e2x5ex+6=0e^{2x} - 5e^x + 6 = 0.
  4. Solve log5(x+1)+log5(x1)=1\log_5(x+1) + \log_5(x-1) = 1.
  5. Solve ex+ex=5e^x + e^{-x} = 5.

Tip: When solving logarithmic equations, always check for domain restrictions like x>0x > 0.

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Math Problem Analysis

Mathematical Concepts

Exponential Equations
Logarithmic Equations
Quadratic Equations
Properties of Logarithms

Formulas

Quadratic equation: ax^2 + bx + c = 0
Logarithmic property: log_b(A) + log_b(B) = log_b(A * B)

Theorems

Quadratic Formula: x = [-b ± sqrt(b^2 - 4ac)] / 2a
Logarithmic equality: If log_b(A) = log_b(B), then A = B

Suitable Grade Level

Grades 9-11