Tìm x: -1/x -1 + 2x^2 - 5/x^3-1 = 4/x^2 + x + 1 Tham khảo câu trả lời từ Trợ lý ảo Lazi To solve the equation \[ -\frac{1}{x} - 1 + 2x^2 - \frac{5}{x^3 - 1} = \frac{4}{x^2 + x + 1}, \] we need to find the values of \( x \) that satisfy this equation. Let's proceed step by step. First, let's rewrite the equation for clarity: \[ -\frac{1}{x} - 1 + 2x^2 - \frac{5}{x^3 - 1} = \frac{4}{x^2 + x + 1}. \] ### Step 1: Simplify the Denominators Notice that \( x^3 - 1 \) can be factored using the difference of cubes: \[ x^3 - 1 = (x - 1)(x^2 + x + 1). \] So, the term \(\frac{5}{x^3 - 1}\) can be rewritten as: \[ \frac{5}{(x - 1)(x^2 + x + 1)}. \] ### Step 2: Common Denominator To combine the terms on the left-hand side, we need a common denominator. The common denominator for the terms involving \( x \) and \( x^3 - 1 \) is \( x(x^3 - 1) \): \[ x(x^3 - 1) = x(x - 1)(x^2 + x + 1). \] ### Step 3: Rewrite Each Term with the Common Denominator Rewrite each term with the common denominator \( x(x - 1)(x^2 + x + 1) \): 1. \(-\frac{1}{x}\): \[ -\frac{1}{x} = -\frac{(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)} = -\frac{x^3 - 1}{x(x - 1)(x^2 + x + 1)}. \] 2. \(-1\): \[ -1 = -\frac{x(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)} = -\frac{x(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)}. \] 3. \(2x^2\): \[ 2x^2 = \frac{2x^2 \cdot x(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)} = \frac{2x^2 \cdot x(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)}. \] 4. \(-\frac{5}{x^3 - 1}\): \[ -\frac{5}{x^3 - 1} = -\frac{5}{(x - 1)(x^2 + x + 1)} = -\frac{5x}{x(x - 1)(x^2 + x + 1)}. \] ### Step 4: Combine the Terms Combine all the terms over the common denominator: \[ -\frac{x^3 - 1}{x(x - 1)(x^2 + x + 1)} - \frac{x(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)} + \frac{2x^2 \cdot x(x - 1)(x^2 + x + 1)}{x(x - 1)(x^2 + x + 1)} - \frac{5x}{x(x - 1)(x^2 + x + 1)} = \frac{4}{x^2 + x + 1}. \] ### Step 5: Simplify the Numerator Combine the numerators: \[ -\left(x^3 - 1\right) - x(x - 1)(x^2 + x + 1) + 2x^3(x - 1)(x^2 + x + 1) - 5x = 4. \] ### Step 6: Solve the Equation This equation is quite complex and may require numerical methods or further algebraic manipulation to solve. Alternatively, we can check for specific values of \( x \) that might satisfy the equation. ### Step 7: Check Specific Values Let's check if \( x = 1 \) is a solution: \[ -\frac{1}{1} - 1 + 2(1)^2 - \frac{5}{(1)^3 - 1} = \frac{4}{(1)^2 + 1 + 1}. \] Simplify: \[ -1 - 1 + 2 - \frac{5}{0} = \frac{4}{3}. \] Since \(\frac{5}{0}\) is undefined, \( x = 1 \) is not a solution. ### Conclusion The equation is complex and may not have a simple analytical solution. It might be best to use numerical methods or graphing techniques to find approximate solutions.