algebra · worked example

Solve system: 3x+2y=12 and x-y=1

Method: 代入法. Verified step-by-step solution with our free AI math solver.
Problem

{3x+2y=12xy=1\begin{cases} 3x + 2y = 12 \\ x - y = 1 \end{cases}

Step-by-step solution

  1. 2番目の式を xx について解きます:x=y+1x = y + 1

  2. 1番目の式に代入します:3(y+1)+2y=123(y + 1) + 2y = 12

  3. 展開します:3y+3+2y=123y + 3 + 2y = 12、よって 5y=95y = 9

  4. 解きます:y=95y = \tfrac{9}{5}

  5. 逆に代入し戻します:x=95+1=145x = \tfrac{9}{5} + 1 = \tfrac{14}{5}

Answer

(x,y)=(145, 95)(x, y) = \bigl(\tfrac{14}{5},\ \tfrac{9}{5}\bigr)

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