What is the solution of equation 4+x=2x-8 is x=
方程4+x=2x-8的解是x=多少
<gadget id="calculator">4 + 8</gadget>
<output>12</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">12 / 1</gadget>
<output>12</output>

<result>12</result>