(2/7) plus (4/5) meters of a rope is exactly equal to itself. What is the length of this rope in meters? What is the column
一根绳子的(2/7)加上(4/5)米，正好等于它本身，这根绳子的长是多少米？列式是多少
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(4/5) / (5/7)</gadget>
<output>28/25 = around 1.12</output>

<result>28/25 = around 1.12</result>