algebra · worked example

Solve 2x² + 7x + 3 = 0 — x = -1/2 or x = -3

Method: AC 法(因式分解). Verified step-by-step solution with our free AI math solver.
Problem

2x2+7x+3=02x^2 + 7x + 3 = 0

Step-by-step solution

  1. 確定 a=2a = 2b=7b = 7c=3c = 3

  2. 計算 ac=23=6ac = 2 \cdot 3 = 6。找出兩個相乘為 66、相加為 b=7b = 7 的數:就是 1166

  3. 拆開中間項:2x2+x+6x+32x^2 + x + 6x + 3

  4. 透過分組因式分解:x(2x+1)+3(2x+1)=(2x+1)(x+3)x(2x + 1) + 3(2x + 1) = (2x + 1)(x + 3)

  5. 令每個因式為零:x=12x = -\tfrac{1}{2}x=3x = -3

Answer

x=12orx=3x = -\tfrac{1}{2} \quad \text{or} \quad x = -3

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