Solve the equation: (3x+4)+x=7(x-5)
解方程：(3x+4)+x=7(x-5)
<gadget id="calculator">7 * 5</gadget>
<output>35</output>

<gadget id="calculator">4 + 35</gadget>
<output>39</output>

<gadget id="calculator">7 - 3 - 1</gadget>
<output>3</output>

<gadget id="calculator">39 / 3</gadget>
<output>13</output>

<result>13</result>