If a and b are reciprocals of each other, and (7/(a))=((b)/(x)), then what is 2x equal to?
如果a与b互为倒数，且(7/(a))=((b)/(x))，那么2x等于多少．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

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

<gadget id="calculator">(1/7) / 1</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/7) * 2</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>