Solve the equation: ((x+3)/(1.6))=((x-9)/(0.4)).
解方程：((x+3)/(1.6))=((x-9)/(0.4))．
<gadget id="calculator">3 * 0.4</gadget>
<output>1.2</output>

<gadget id="calculator">9 * 1.6</gadget>
<output>14.4</output>

<gadget id="calculator">1.2 + 14.4</gadget>
<output>15.6</output>

<gadget id="calculator">1.6 - 0.4</gadget>
<output>1.2</output>

<gadget id="calculator">15.6 / 1.2</gadget>
<output>13</output>

<result>13</result>