If 3.5*(6.8-(1.6+△/0.9))/8.4=0.5, find the value of △.
若3.5*(6.8-(1.6+△/0.9))/8.4=0.5，求△的值．
<gadget id="calculator">0.5 / 3.5</gadget>
<output>0.142857</output>

<gadget id="calculator">8.4 * 0.142857</gadget>
<output>1.199999</output>

<gadget id="calculator">6.8 - 1.199999 - 1.6</gadget>
<output>4.000001</output>

<gadget id="calculator">4.000001 * 0.9</gadget>
<output>3.600001</output>

<result>3.600001</result>