Given that 2x-1 and -13 are opposite numbers, find the value of x.
已知2x-1与-13互为相反数，求x的值．
<gadget id="calculator">0 + 14</gadget>
<output>14</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<result>7</result>